Annotate mapped memory regions for LeakSanitizer.

Annotate mapped memory regions for LeakSanitizer.

Add in-code annotations for LeakSanitizer to treat any memory allocated through
the VirtualMemory class as a source of live pointers. This change eliminates
false positive leak reports when running Chromium under LSan.

BUG=chromium:328552
R=mstarzinger@chromium.org
LOG=Y

Committed: https://code.google.com/p/v8/source/detail?r=18589

[earthdok, 2014-01-13 20:24:29]

Please take a look. With the lastest clang roll in Chromium we can finally
commit this.

[Michael Starzinger, 2014-01-14 13:37:45]

LGTM. I will land this.

[earthdok, 2014-01-14 13:47:38]

On 2014/01/14 13:37:45, Michael Starzinger wrote:
> LGTM. I will land this.

Thanks!

[Michael Starzinger, 2014-01-14 14:00:35]

Committed patchset #1 manually as r18589 (presubmit successful).