[coverage] Always merge sancov files after testing.

tools/run-tests.py

 #!/usr/bin/env python
 #
 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 808 matching lines @@
     verbose.PrintTestDurations(suites, overall_duration)
 
   if num_tests == 0:
     print("Warning: no tests were run!")
 
   if exit_code == 1 and options.json_test_results:
     print("Force exit code 0 after failures. Json test results file generated "
           "with failure information.")
     exit_code = 0
 
+  if options.sancov_dir:
+    # If tests ran with sanitizer coverage, merge coverage files in the end.
+    try:
+      print "Merging sancov files."
+      subprocess.check_call([
+        sys.executable,
+        join(BASE_DIR, "tools", "sanitizers", "sancov_merger.py"),
+        "--coverage-dir=%s" % options.sancov_dir])
+    except:
+      print >> sys.stderr, "Error: Merging sancov files failed."
+      exit_code = 1
+
   return exit_code
 
 
 if __name__ == "__main__":
   sys.exit(Main())