Clean up option parsing in tools/clang/scripts/run_tool.py
Clean up option parsing in tools/clang/scripts/run_tool.py

Also remove built-in clang formatting, since git cl format does the same
thing and works everywhere.

BUG=none

Review URL: https://codereview.chromium.org/1519563005

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#364814}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk