android: Enable death on malloc/operator new failure.

1. Historically the OnNoMemory suicide on malloc/new failure was not
enabled on Android. This seems to be due to the fact that
set_new_handler was not avilable on Android back in the days of
pre-libcxx. See crbug.com/317791 .

2. After the libcxx switch, however, the combination of operator new
throwing bad_alloc and chrome building with -fno-exception made
operator new (but not malloc) inadvertently suicidal, by virtue of
ending up calling the default exception handler.
See crbug.com/633313#c28 .

3. crrev.com/1883093005 (first seen in M52) introduced a shim layer
wrapping malloc and operator new, which was intending, among the
various things, to make malloc / new finally secure on Android.
This good intend, however, failed to materialize because the
set_new_handler call in memory_linux.cc was still #ifdef-ed out
on Android. Similarly the memory_unittests.cc were excluded on
Android for the same reason (Android was deemed to not possibly
be secure since 1.).

In summary here's what went wrong:
- When we switched to libcxx, nobody realized that we could have
  finally taken advantage of set_new_handler.
- When I enabled the android shim I didn't realize about the
  missing set_new_handler call. I was assuming that the memory
  tests would have screamed red if I did something wrong, but I
  didn't realize that they were disabled on Android.

This CL fixes all this, enabling set_new_handler on Android and
enabling the tests.

Note also that this CL is just about inducing a hard crash on malloc failure.
This does not change the situation about disallowing large allocations
(>2GB) that might cause int signed/unsigned bugs
(see crbug.com/169327). As things stand today, Android never had that
check and still doesn't yet after this CL.

BUG=633966,317791
TEST=base_unittests --gtest_filter=OutOfMemory*

Review-Url: https://codereview.chromium.org/2201363002
Cr-Original-Commit-Position: refs/heads/master@{#409531}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 227dbd3dc564004471f146ef655fad35c52704c3

android/pylib/gtest/filter/base_unittests_disabled

@@ -17,8 +17,6 @@ StringPrintfTest.StringPrintfBounds
 FieldTrialTest.*
 # Flaky?
 ScopedJavaRefTest.RefCounts
-# Death tests are not supported with apks.
-*DeathTest*
 FileTest.MemoryCorruption
 MessagePumpLibeventTest.QuitOutsideOfRun
 ScopedFD.ScopedFDCrashesOnCloseFailure