Hook up show-config to testing scripts.

testing/tools/run_javascript_tests.py

Index: testing/tools/run_javascript_tests.py
diff --git a/testing/tools/run_javascript_tests.py b/testing/tools/run_javascript_tests.py
index 0c2401774e6cd4d95617a8e239d23017b4a99a08..b09ea49e788e19f699a10373305d6787ea6b2e9a 100755
--- a/testing/tools/run_javascript_tests.py
+++ b/testing/tools/run_javascript_tests.py
@@ -63,6 +63,11 @@ def main():
   if not os.path.exists(working_dir):
     os.makedirs(working_dir)
 
+  feature_string = subprocess.check_output([pdfium_test_path, '--show-config'])
+  if "V8" not in feature_string.strip().split(","):
+    print "V8 not enabled, skipping."
+    return 0
+
   input_files = []
   if len(args):
     for file_name in args: