Make blink_heap_unittests link in static_library Debug builds on Windows
Make blink_heap_unittests link in static_library Debug builds on Windows

It was failing to link due to multiple definitions of memory
allocation functions (in both 32- and 64-bit builds). It seems
we don't have any buildbots exercising this configuration.

BUG=429498

Review URL: https://codereview.chromium.org/696233002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@184793 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs