[test] Fix asan default options for gyp builds

Allowing a user handler for segv is default in GN, but not in GYP. We pass it now explicitly to make the last gyp bot temporarily happy.

TBR=vogelheim@chromium.org

Bug: chromium:710409
Change-Id: Ib997245f348481158bd8d64192ac653b60237452
Reviewed-on: https://chromium-review.googlesource.com/474147Reviewed-by: Daniel Vogelheim <vogelheim@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44578}

tools/run-tests.py

@@ -403,7 +403,7 @@ def SetupEnvironment(options):
   )
 
   if options.asan:
-    asan_options = [symbolizer]
+    asan_options = [symbolizer, "allow_user_segv_handler=1"]
     if not utils.GuessOS() == 'macos':
       # LSAN is not available on mac.
       asan_options.append('detect_leaks=1')