disable unittests under ASAN that use memory crashes

There are a bunch of tests that use invalid memory acesses (on purpose)
to trigger a crash so that we can detect things are dumped correctly.
When we run under ASAN, it catches those accesses and the breaks the
testing flow.

For now, use the existing ADDRESS_SANITIZER symbol to disable more tests.
Ideally we'd use a compile-time attribute to disable ASAN on a few funcs,
but that seems to be broken atm.

BUG=chromium:293519
BUG=chromium:304575
TEST=ran unittests under ASAN and they now pass
TEST=ran unittests w/out asan/clang and they still pass
R=benchan@chromium.org

Review URL: https://breakpad.appspot.com/884002

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1255 4c0a9323-5329-0410-9bdc-e9ce6186880e