adb_gdb: AddressSanitizer support.

When running with AddressSanitizer, the main executable of Android
applications is /system/bin/app_process.real instead of the usual
/system/bin/app_process. This change helps adb_gdb detect this
situation.

See tools/android/asan/asan_device_setup.sh for more details.

R=bulach@chromium.org, digit@chromium.org
BUG=

Review URL: https://codereview.chromium.org/150233002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248186 0039d316-1c4b-4281-b951-d872f2087c98
android envsetup: Stop adding NDK to PATH.

The only binaries in there are ndk-build, ndk-gdb, ndk-stack, and ndk-which,
neither of which is used with chromium.

BUG=330631

Review URL: https://codereview.chromium.org/141853005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248187 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248186
android envsetup: Stop explicitly setting host_arch when target_arch=x86.

The explicit setting seems to match the default value for host_arch in
build/common.gypi close to line 110, and it's not set explicitly for other
target_archs, so this looks like an oversight. It's been this way since this
file was added in r148790 18 months ago.

No intended behavior change.

BUG=330631

Review URL: https://codereview.chromium.org/142023006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248188 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248188