Create run_javascript_tests.py

Top level script driver for testing/resources/javascript.
Converts each input template file in that directory to a
.pdf file in the working directory (typically
out/Debug/gen/pdfium/testing/resources/javascript), invokes
pdfium_test on it to generate , and crudely diffs the
expected output.

We can now remove generated .pdfs from source control,
keeping only the hand-editable .in templates.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/912803004
4 files changed