Vulkan: Async compile pipelines with different surface rotations Add prepareForWarmUpPipelineCache(...) method to ProgramExecutableVk that sets up the required common state for warmup tasks. On platforms that support worker threads enqueue a warmup task per surface rotation. Bug: angleproject:8601 Change-Id: I22c0d664736ef682d4207c1e08163f79ac79f7d0 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5366173 Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: mohan maiya <m.maiya@samsung.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>