Remove the (deprecated) isOpaque parameter when making SkSL shaders

SkSL now deduces this, so the parameter does nothing, and is going away.

Bug: 217753125
Change-Id: I673537a9900b5d3219f3914b3b93e0b5e97329db
Test: Removal of unused parameter. Existing tests still pass.
diff --git a/libs/hwui/effects/StretchEffect.cpp b/libs/hwui/effects/StretchEffect.cpp
index 8cb4515..2757c39 100644
--- a/libs/hwui/effects/StretchEffect.cpp
+++ b/libs/hwui/effects/StretchEffect.cpp
@@ -227,7 +227,7 @@
     mBuilder->uniform("viewportWidth").set(&width, 1);
     mBuilder->uniform("viewportHeight").set(&height, 1);
 
-    auto result = mBuilder->makeShader(nullptr, false);
+    auto result = mBuilder->makeShader();
     mBuilder->child(CONTENT_TEXTURE) = nullptr;
     return result;
 }