Metal: Move setupDraw and associated code to executable Last bits of state left in ProgramMtl that are now moved to ProgramExecutableMtl, and now ContextMtl does not reference the program at all. This fix was necessary for a follow up change that allows the program to be modified while the executable is installed, and the metal backend was crashing after a failed relink due its direct access to the program. Bug: angleproject:8297 Change-Id: Iadf623bf6baf612767ff372adee2e7f4eeedb593 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4833624 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>