State: Add dirty object for active textures. Checking sampler completeness after every sampler related state change is inefficient. Defer sampler completeness check to draw time. Based on a CL by hckim.kim@samsung.com. Bug: angleproject:4765 Tests: angle_perftests.exe --gtest_filter=TexturesBenchmark.* Change-Id: I7e971371e40b3044ca3d5ca39bfe7fc600620c3e Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2268577 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Geoff Lang <geofflang@chromium.org>