[compiler-rt][asan|win] Fix ASAN exception handler missing import

Summary:
This patch is adding a missing ASAN API redirection from an instrumented DLL.
The bug was introduced here:
  https://reviews.llvm.org/D29463

This is causing this chromium bug:
  https://bugs.chromium.org/p/chromium/issues/detail?id=692580

Reviewers: rnk

Reviewed By: rnk

Subscribers: kubamracek, dberris, llvm-commits, chrisha, thakis

Differential Revision: https://reviews.llvm.org/D30001

llvm-svn: 295232

compiler-rt/lib/asan/asan_win_dll_thunk.cc

@@ -100,6 +100,7 @@ INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
 // Window specific functions not included in asan_interface.inc.
 INTERCEPT_WRAP_W_V(__asan_should_detect_stack_use_after_return)
 INTERCEPT_WRAP_W_V(__asan_get_shadow_memory_dynamic_address)
+INTERCEPT_WRAP_W_W(__asan_unhandled_exception_filter)
 
 using namespace __sanitizer;