CL/Vulkan: Add initial profiling support This PR introduces initial cl_event profiling support. For now, use CPU timestamps (later look into Vulkan GPU device timestamps). Bug: angleproject:357902512 Change-Id: I2197e396e222d2842ab31304f91934f9e000ea0d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5767598 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Austin Annestrand <a.annestrand@samsung.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>