llvm_tools: s/chroot_path/chromeos_path

This path talks about a ChromeOS source tree, not a chroot. The flag
should reflect that.

I had to change a few scripts simultaneously, since these all depend on
`test_helpers` for `chroot_path`.

BUG=b:325884106, b:325895866
TEST=Unittests

Change-Id: Ie6e8a5ca62257e6b2b49f0a688d06da45715f50c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/5360712
Reviewed-by: Jordan Abrahams-Whitehead <ajordanr@google.com>
Commit-Queue: George Burgess <gbiv@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
13 files changed