[coverage] Enable sanitizer coverage.

build/coverage_wrapper.py

 #!/usr/bin/env python
 # Copyright 2016 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # CC/CXX wrapper script that excludes certain file patterns from coverage
 # instrumentation.
 
 import re
 import subprocess
 import sys
 
 exclusions = [
+  'buildtools',
   'src/third_party',
   'third_party',
   'test',
   'testing',
 ]
 
+def remove_failsafe(string_list, item):
+  try:
+    string_list.remove(item)
+  except:
+    pass
+
 args = sys.argv[1:]
 text = ' '.join(sys.argv[2:])
 for exclusion in exclusions:
   if re.search(r'\-o obj/%s[^ ]*\.o' % exclusion, text):
-    args.remove('-fprofile-arcs')
-    args.remove('-ftest-coverage')
+    remove_failsafe(args, '-fprofile-arcs')
+    remove_failsafe(args, '-ftest-coverage')
+    remove_failsafe(args, '-fsanitize-coverage=func')
+    remove_failsafe(args, '-fsanitize-coverage=bb')
+    remove_failsafe(args, '-fsanitize-coverage=edge')
     break
 
 sys.exit(subprocess.check_call(args))