Issue 1:
Some tests are not compatible with Android-L's security model.

Some tests (involving processing stderr/stdout of child processes) are confused.

Here is error messages after patching cl/12559 (for pie)

WARNING: linker: /data/local/tmp/syslog.test-50176/syslog.test-50176 has text relocations. This is wasting memory and prevents security hardening. Please fix.
2015/08/21 13:44:14 startServer failed: listen unix /data/local/tmp/syslog.test-50176/syslogtest840502310: bind: permission denied
exitcode=1go_android_exec: adb shell rm -rf /data/local/tmp/syslog.test-50176
FAIL log/syslog 1.981s

--- FAIL: TestConnAndListener (0.00s)
conn_test.go:29: listen unix /data/local/tmp/net.test-50439/go-nettest156564319: bind: permission denied
--- FAIL: TestCloseRead (0.00s)
net_test.go:28: listen unix /data/local/tmp/net.test-50439/go-nettest558273769: bind: permission denied
--- FAIL: TestCloseWrite (0.00s)
net_test.go:114: listen unix /data/local/tmp/net.test-50439/go-nettest743620916: bind: permission denied
--- FAIL: TestConnClose (0.00s)
net_test.go:164: listen unix /data/local/tmp/net.test-50439/go-nettest612674819: bind: permission denied
--- FAIL: TestListenerClose (0.00s)
net_test.go:205: listen unix /data/local/tmp/net.test-50439/go-nettest021369990: bind: permission denied
--- FAIL: TestPacketConnClose (0.00s)
net_test.go:236: listen unixgram /data/local/tmp/net.test-50439/go-nettest185898029: bind: permission denied
--- FAIL: TestPacketConn (0.00s)
packetconn_test.go:57: listen unixgram /data/local/tmp/net.test-50439/go-nettest041550039: bind: permission denied
--- FAIL: TestConnAndPacketConn (0.00s)
packetconn_test.go:112: listen unixgram /data/local/tmp/net.test-50439/go-nettest041550039: bind: permission denied
--- FAIL: TestUnixListenerSpecificMethods (0.00s)
protoconn_test.go:215: listen unix /data/local/tmp/net.test-50439/go-nettest385819048: bind: permission denied
--- FAIL: TestUnixConnSpecificMethods (0.00s)
protoconn_test.go:257: dial unixgram /data/local/tmp/net.test-50439/go-nettest314342631: bind: permission denied
--- FAIL: TestUnixAndUnixpacketServer (0.00s)
server_test.go:151: listen unix /data/local/tmp/net.test-50439/go-nettest512301857: bind: permission denied
--- FAIL: TestUnixgramServer (0.00s)
server_test.go:341: listen unixgram /data/local/tmp/net.test-50439/go-nettest015628795: bind: permission denied
--- FAIL: TestReadUnixgramWithUnnamedSocket (0.00s)
unix_test.go:31: listen unixgram /data/local/tmp/net.test-50439/go-nettest721342812: bind: permission denied
--- FAIL: TestUnixgramZeroBytePayload (0.00s)
unix_test.go:77: listen unixgram /data/local/tmp/net.test-50439/go-nettest064747275: bind: permission denied
--- FAIL: TestUnixgramZeroByteBuffer (0.00s)
unix_test.go:127: listen unixgram /data/local/tmp/net.test-50439/go-nettest691965678: bind: permission denied
--- FAIL: TestUnixgramWrite (0.00s)
unix_test.go:225: listen unixgram /data/local/tmp/net.test-50439/go-nettest293440885: bind: permission denied
--- FAIL: TestUnixConnLocalAndRemoteNames (0.00s)
unix_test.go:301: listen unix /data/local/tmp/net.test-50439/go-nettest721800559: bind: permission denied
--- FAIL: TestUnixgramConnLocalAndRemoteNames (0.00s)
unix_test.go:363: listen unixgram /data/local/tmp/net.test-50439/go-nettest607627129: bind: permission denied
FAIL
exitcode=1go_android_exec: adb shell rm -rf /data/local/tmp/net.test-50439
FAIL net 5.456s

--- FAIL: TestLongSymlink (0.00s)
os_test.go:690: symlink "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", "longsymlinktestfrom" failed: symlink 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef longsymlinktestfrom: permission denied
--- FAIL: TestGetppid (0.02s)
os_test.go:1615: Child process reports parent process id 'WARNING: linker: /data/local/tmp/os.test-50530/os.test-50530 has text relocations. This is wasting memory and prevents security hardening. Please fix.
13739', expected '13739'
--- FAIL: TestMkdirAllWithSymlink (0.00s)
path_test.go:196: Symlink /data/local/tmp/os.test-50530/TestMkdirAllWithSymlink-447302546/link: symlink dir /data/local/tmp/os.test-50530/TestMkdirAllWithSymlink-447302546/link: permission denied
FAIL
exitcode=1go_android_exec: adb shell rm -rf /data/local/tmp/os.test-50530
FAIL os 2.132s

....
exec_test.go:543: iteration 9, process B got:
WARNING: linker: /data/local/tmp/exec.test-50565/exec.test-50565 has text relocations. This is wasting memory and prevents security hardening. Please fix.
fd3: listener 127.0.0.1:33373

want:
fd3: listener 127.0.0.1:33373

FAIL
exitcode=1go_android_exec: adb shell rm -rf /data/local/tmp/exec.test-50565
FAIL os/exec 2.826s

--- FAIL: TestGlobSymlink (0.00s)
match_test.go:197: symlink /data/local/tmp/filepath.test-50618/globsymlink620110739/test1 /data/local/tmp/filepath.test-50618/globsymlink620110739/link1: permission denied
--- FAIL: TestEvalSymlinks (0.00s)
path_test.go:796: symlink ../../ /data/local/tmp/filepath.test-50618/evalsymlink112903032/test/dir/link3: permission denied
FAIL
exitcode=1go_android_exec: adb shell rm -rf /data/local/tmp/filepath.test-50618
FAIL path/filepath 0.911s

--- FAIL: TestFcntlFlock (0.08s)
syscall_unix_test.go:98: child process: "WARNING: linker: /data/local/tmp/syscall.test-50825/syscall.test-50825 has text relocations. This is wasting memory and prevents security hardening. Please fix.\n",
--- FAIL: TestPassFD (0.10s)
syscall_unix_test.go:166: child process: "WARNING: linker: /data/local/tmp/syscall.test-50825/syscall.test-50825 has text relocations. This is wasting memory and prevents security hardening. Please fix.\n",
FAIL
exitcode=1go_android_exec: adb shell rm -rf /data/local/tmp/syscall.test-50825
FAIL syscall 1.802s

/cc @crawshaw

Issue 2:
The current builder cross-compiles the test binaries, runs the compiled binaries on the device, and parses the output of them. This does not work for android-L that requires PIE and refuses to run the test binaries with the following error message.

"only position independent executables (PIE) are supported."

Probably related to : #6940