cmd/go: clarify test filenames in help messages
Fixes issue 5655.

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/9944044
cmd/go: diagnose invalid coverage runs

# bufio
coverage analysis cannot handle package (bufio_test imports testing imports bufio)
# bytes
coverage analysis cannot handle package (bytes_test imports encoding/base64 imports bytes)
# crypto/cipher
coverage analysis cannot handle package (cipher_test imports crypto/aes imports crypto/cipher)
# debug/dwarf
coverage analysis cannot handle package (dwarf_test imports debug/elf imports debug/dwarf)
# errors
coverage analysis cannot handle package (errors_test imports fmt imports errors)
# flag
coverage analysis cannot handle package (flag_test imports testing imports flag)
# fmt
coverage analysis cannot handle package (fmt_test imports testing imports fmt)
# go/ast
coverage analysis cannot handle package (ast_test imports go/format imports go/ast)
# image
coverage analysis cannot handle package (image_test imports image/gif imports image)
# io
coverage analysis cannot handle package (io_test imports bytes imports io)
# math
coverage analysis cannot handle package (math_test imports fmt imports math)
# net/http
coverage analysis cannot handle package (http_test imports net/http/httptest imports net/http)
# os
coverage analysis cannot handle package (os_test imports flag imports os)
# path/filepath
coverage analysis cannot handle package (filepath_test imports io/ioutil imports path/filepath)
# reflect
coverage analysis cannot handle package (reflect_test imports flag imports reflect)
# runtime
coverage analysis cannot handle package (runtime_test imports fmt imports runtime)
# runtime/pprof
coverage analysis cannot handle package (pprof_test imports testing imports runtime/pprof)
# sort
coverage analysis cannot handle package (sort_test imports testing imports sort)
# strconv
coverage analysis cannot handle package (strconv_test imports fmt imports strconv)
# strings
coverage analysis cannot handle package (strings_test imports testing imports strings)
# sync
coverage analysis cannot handle package (sync_test imports fmt imports sync)
# sync/atomic
coverage analysis cannot handle package (atomic_test imports testing imports sync/atomic)
# syscall
coverage analysis cannot handle package (syscall_test imports flag imports syscall)
# text/tabwriter
coverage analysis cannot handle package (tabwriter_test imports testing imports text/tabwriter)
# time
coverage analysis cannot handle package (time_test imports encoding/gob imports time)
# unicode
coverage analysis cannot handle package (unicode_test imports testing imports unicode)
# unicode/utf8
coverage analysis cannot handle package (utf8_test imports bytes imports unicode/utf8)

R=r
CC=golang-dev
https://codereview.appspot.com/10216043
runtime: adjust traceback / garbage collector boundary

The garbage collection routine addframeroots is duplicating
logic in the traceback routine that calls it, sometimes correctly,
sometimes incorrectly, sometimes incompletely.
Pass necessary information to addframeroots instead of
deriving it anew.

Should make addframeroots significantly more robust.
It's certainly smaller.

Also try to standardize on uintptr for saved pc, sp values.

Will make CL 10036044 trivial.

R=golang-dev, dave, dvyukov
CC=golang-dev
https://codereview.appspot.com/10169045
runtime: fix build

TBR=dvyukov
CC=golang-dev
https://codereview.appspot.com/10227044
runtime: fix plan9, windows builds

TBR=dvyukov
CC=golang-dev
https://codereview.appspot.com/10229043
runtime: fix scheduler race condition
In starttheworld() we assume that P's with local work
are situated in the beginning of idle P list.
However, once we start the first M, it can execute all local G's
and steal G's from other P's.
That breaks the assumption above. Thus starttheworld() will fail
to start some P's with local work.
It seems that it can not lead to very bad things, but still
it's wrong and breaks other assumtions
(e.g. we can have a spinning M with local work).
The fix is to collect all P's with local work first,
and only then start them.

R=golang-dev, rsc
CC=golang-dev
https://codereview.appspot.com/10051045
runtime: more flexible heap memory mapping on 64-bits
Fixes issue 5641.

R=golang-dev, dave, daniel.morsing, iant
CC=golang-dev, kcc
https://codereview.appspot.com/10126044