Disable OES_primitive_bounding_box on unsupported contexts The OES_primitive_bounding_box extension requires OpenGL ES 3.1 and must not be exposed on lower context versions. Also made both EXT and OES versions of this extension enableable. Bug: angleproject:42262238 Bug: angleproject:415495316 Change-Id: I5379daa06dba3b2b09d9656ffab15c010fb4870a Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6538627 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>