There was a bug that if there is a pending update in the immutable
texture's level that is outside of [base, max], and then when you render
to that level, the pending update will not get flushed. This test verify
this bug.
Bug: b/181800403
Test: FramebufferTest_ES3.RenderImmutableTextureWithSubImageWithBeyondMaxLevel
Change-Id: Id9a5a141d26d45a3a154c331086bb64b0b094cdf
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2797724Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Ian Elliott <ianelliott@google.com>
Commit-Queue: Charlie Lao <cclao@google.com>
