The frame-capture-specific AndroidGetEnvFromProp() function has been
ported to the general utility, GetEnvironmentVarFromAndroidProperty().

Bug: b/170249632
Change-Id: I97de8205ceef140dfd8fab8e6f2d52b90cd996cf
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2502772Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Ian Elliott <ianelliott@google.com>