Fixed issue where HardwareBufferRenderer was not preserving contents

Updated RenderProxy creation to pass false for the opaque flag
in order to avoid an unnecessary canvas->clear invocation within
SkiaPipeline::draw

Fixes: 275398000
Test: Added test to HardwareBufferRendererTests
Change-Id: I5f884240439bf3e57500ed1404f31fbe2ea122fa
diff --git a/libs/hwui/pipeline/skia/SkiaPipeline.cpp b/libs/hwui/pipeline/skia/SkiaPipeline.cpp
index 6628463..8ea71f1 100644
--- a/libs/hwui/pipeline/skia/SkiaPipeline.cpp
+++ b/libs/hwui/pipeline/skia/SkiaPipeline.cpp
@@ -499,8 +499,7 @@
     }
     canvas->concat(preTransform);
 
-    // STOPSHIP: Revert, temporary workaround to clear always F16 frame buffer for b/74976293
-    if (!opaque || getSurfaceColorType() == kRGBA_F16_SkColorType) {
+    if (!opaque) {
         canvas->clear(SK_ColorTRANSPARENT);
     }