toolchain-utils: fix shebang related lint warnings.

This CL fixes all missing-shebang and bad-shebang lint warnings.

BUG=chromium:570458
TEST='crosperf/run_tests.sh' passes.

Change-Id: I41bd3516496b246e4e4a8ccc9f97fb25007738a7
Reviewed-on: https://chrome-internal-review.googlesource.com/243136
Commit-Ready: Rahul Chaudhry <rahulchaudhry@google.com>
Tested-by: Rahul Chaudhry <rahulchaudhry@google.com>
Reviewed-by: Luis Lozano <llozano@chromium.org>
15 files changed