Previously glAttachShader and glDetachShader would only call
resolveLink during validation.

Adding the resolveLink in attachShader/detachShader handles the case
where glAttachShader and glDetachShader is called with
EGL_CONTEXT_OPENGL_NO_ERROR_KHR to skip validation.

Tests: angle_end2end_tests --gtest_filter=ContextNoErrorTest.DetachAfterLink*
Bug: angleproject:2868
Change-Id: I1e01cf8e6f8a382333226bdef037c46f4c62a119
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2745654Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Mohan Maiya <m.maiya@samsung.com>