compiler_wrapper: Replace UserHomeDir uses.

os.UserHomeDir is not available in the Go version in Cros SDK.
Replace by explicit env value of "HOME".

BUG=None
TEST=go test

Change-Id: Ia0da2d9bce042510fcc1b14cb074dadfe4d0f2f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1856381
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Tobias Bosch <tbosch@google.com>
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
10 files changed