Also includes moving these two (and some helpers) to
common/system_utils.h
Bug: angleproject:5095
Change-Id: I7d2fcbd27a67dc13215265ac5b5e8391b15a980b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3733519
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Eddie Hatfield <eddiehatfield@google.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>