Add tests for C++ exception types that use virtual base classes

Add tests for C++ exception types that use virtual base classes

Matching an exception against a virtual base class requires
dereferencing the exception and its vtable (unlike with non-virtual
base classes), so this tests that the correct exception pointer is
passed to exception_spec_can_catch() in libcxxabi (or
check_exception_spec() in libsupc++).

Also add a test to check that exception specs work when the exception
is allowed by the exception spec.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3696
TEST=run_eh_throw_tests_sjlj_test

Committed: https://src.chromium.org/viewvc/native_client?view=rev&revision=12492

[Derek Schuff, 2013-12-05 01:21:31]

lgtm

[Mark Seaborn, 2013-12-05 01:33:21]

Committed patchset #1 manually as r12492 (presubmit successful).