Removal global locks from GL entry points. Always lock in EGL. The ANGLE Vulkan backend is now thread safe for non-share group contexts. This means that a global GL lock only adds overhead for most use cases. Remove the angle_force_thread_safety gn argument. BUG=angleproject:2464 Change-Id: Ic6ba89e18b46e5dd72aa83d0f409097441fcca3a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1635749 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Tobin Ehlis <tobine@google.com>