Don't build OpenCL with msvc msvc builds of llvm take way too long. We make sure ANGLE builds with msvc to support existing users of it as a GLES implementation, but we have no intention to support the OpenCL implementation with that compiler. Bug: None Change-Id: I1c370fd843fc25cccacabbbfb4727ef830fa45e7 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5539191 Reviewed-by: Yuly Novikov <ynovikov@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>