[CFI] Blacklist breakpad unit tests that call into dynamically allocated memory

BUG=842768

Change-Id: Ic59dcbb02d413d9830e11fd7117307c31ee60621
Reviewed-on: https://chromium-review.googlesource.com/1057948Reviewed-by: Peter Collingbourne <pcc@chromium.org>
Commit-Queue: Peter Collingbourne <pcc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558389}

tools/cfi/blacklist.txt

@@ -188,6 +188,8 @@ src:*third_party/breakpad/breakpad/src/common/linux/http_upload.cc
 # the unit tests do not exercise those code paths. Be careful removing.
 src:*net/http/http_auth_gssapi_posix.cc
 
+src:*third_party/breakpad/breakpad/src/client/linux/handler/exception_handler_unittest.cc
+
 ######### Function pointers cast to incorrect type signatures
 
 # libicu is currently compiled such that in libicu the 'UChar' type is a