Revert "scripts: gcc-wrapper: Use wrapper to check compiler warnings"

gcc-wrapper simulates building with -Werror, but with a few hardcoded
file:line combinations that don't get promoted to errors.

We're already building with -Werror anyway without issue, so this script
is redundant and just adds a dependency on Python 2.

This reverts commit ca2dc1f081b0a15d28b5b0d3f032b89aa819b65c.

Change-Id: Id4a75ff16fb75e7d621c532a37ddcbe0efa01040
Signed-off-by: Greg Hackmann <ghackmann@google.com>