llvm_tools/get_llvm_hash.py: annotate and opt into static type checking

BUG=b:316360063
TEST=presubmit

Change-Id: I5e6fe473465293fd8c1e67e6ff5199c55731abae
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/5143107
Tested-by: Bob Haarman <inglorion@chromium.org>
Reviewed-by: Jordan Abrahams-Whitehead <ajordanr@google.com>
Commit-Queue: Bob Haarman <inglorion@chromium.org>
2 files changed