Revert "Release YUVA planes in SkImage_GpuYUVA after flattenning to RGBA."

This reverts commit a15f355be83136e7827ccfbc9bb9e9ea77f48518.

Reason for revert: ANGLE failing new test

Original change's description:
> Release YUVA planes in SkImage_GpuYUVA after flattenning to RGBA.
> 
> Also removed unused virtual function from SkImage_GpuBase and override
> on SkImage_GpuYUVA.
> 
> Change-Id: Ib47b46b529b16976181cb9453976133d66e0f952
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/212734
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

TBR=jvanverth@google.com,bsalomon@google.com,robertphillips@google.com

Change-Id: Ib2566ff8aa99d3698d6044167e70a1d75542f2e9
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/212986
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrImageTextureMaker.cpp b/src/gpu/GrImageTextureMaker.cpp
index 0fb1cbe..80b39d0 100644
--- a/src/gpu/GrImageTextureMaker.cpp
+++ b/src/gpu/GrImageTextureMaker.cpp
@@ -91,9 +91,8 @@
     bool coordsLimitedToConstraintRect,
     const GrSamplerState::Filter* filterOrNullForBicubic) {
 
-    // Check simple cases to see if we need to fall back to flattening the image (or whether it's
-    // already been flattened.)
-    if (!filterOrNullForBicubic || this->domainNeedsDecal() || fImage->fRGBProxy) {
+    // Check simple cases to see if we need to fall back to flattening the image
+    if (!filterOrNullForBicubic || this->domainNeedsDecal()) {
         return this->INHERITED::createFragmentProcessor(textureMatrix, constraintRect,
                                                         filterConstraint,
                                                         coordsLimitedToConstraintRect,