OpenCL: Replace error-return APIs to use angle::Result The motivation of converting existing CL APIs using "cl_int errorCode" to now use "angle::Result" is for better interop with internal ANGLE plumbing/abstractions. To facilitate this, we now make use of a TLS errorCode object that we set internally and read from entrypoint/stubs layer so that we can propagate back to user. Bug: angleproject:8435 Change-Id: I7c2a786019c33c56649be4b6e8b61bc318497bb1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5075772 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>