Adjust TexStorage2DEXT validation; update tests - Use common texture format support function. - Enforce size restrictions for compressed formats. - Expand CompressedTexture* and WebGLCompatibilityTest.CompressedTexImage* tests. - Adjust GL_DEPTH_COMPONENT16 support condition on ES 2.0. - Adjust GL_DEPTH24_STENCIL8 support condition on ES 2.0. - Adjust GL_RGB10_A2 support condition on ES 2.0; adjust VulkanExternalImageTest.TextureFormatCompatChromium* tests. - Do not use integer formats in TextureRectangleTest.TexStorage2D. Bug: angleproject:5731, angleproject:6230 Change-Id: I2f288f459b511cc004601238df717aa78433be7f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3118553 Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Kenneth Russell <kbr@chromium.org>