[ASan] Turns out we should always intercept __cxa_throw
At least check-asan works with this change.

If the change breaks anything, we'll need to add:
a) a comment describing why we have to use INTERCEPT_FUNCTION rather than
   ASAN_INTERCEPT_FUNC
and
b) a test case.




git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@216177 91177308-0d34-0410-b5e6-96231b3b80d8