Summary:
Adds a python script to syntax check all python files in the
repository and report any errors.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6209
Test Plan:
'make check' with and without seeded syntax errors. Also look
for "No syntax errors in 34 .py files" on success, and in java_test CI output
Differential Revision: D19166756
Pulled By: pdillinger
fbshipit-source-id: 537df464b767260d66810b4cf4c9808a026c58a4
