Fix memory leaks in angle_unittests. Call ShDestruct() to destroy the compiler objects to avoid memory leaks. BUG=angle:737 Change-Id: I71a8ddfe67c9d8c7b4e5b5683c69dd578fc38c66 Reviewed-on: https://chromium-review.googlesource.com/215860 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Sudarsana Nagineni <sudarsana.nagineni@intel.com>