Remove SaveFlags from saveLayer(Alpha)

This has been hardcoded as ALL_SAVE_FLAGS for a couple releases now.

Since it's now permanent behavior, remove the last bit of plumbing
for SaveFlags on saveLayer

Test: builds & boots
Change-Id: Iec92f27199d0b4781c2293dcdcfd45a1562a1b4e
diff --git a/libs/hwui/tests/unit/RenderNodeDrawableTests.cpp b/libs/hwui/tests/unit/RenderNodeDrawableTests.cpp
index 7aa6be8..abdf9d5 100644
--- a/libs/hwui/tests/unit/RenderNodeDrawableTests.cpp
+++ b/libs/hwui/tests/unit/RenderNodeDrawableTests.cpp
@@ -198,7 +198,7 @@
                 EXPECT_TRUE(getRecorderMatrix(recorder).isIdentity());
 
                 // note we don't pass SaveFlags::MatrixClip, but matrix and clip will be saved
-                recorder.saveLayer(0, 0, 400, 400, &layerPaint, SaveFlags::ClipToLayer);
+                recorder.saveLayer(0, 0, 400, 400, &layerPaint);
                 ASSERT_EQ(SkRect::MakeLTRB(0, 0, 400, 400), getRecorderClipBounds(recorder));
                 EXPECT_TRUE(getRecorderMatrix(recorder).isIdentity());