Update hwui_unit_tests to support running with Vulkan backend.

Added Macros for RENDERTHREAD_TESTS which run these tests using specific backends.
RENDERTHREAD_TESTS - Runs OpenGL, SkiaGL, and SkiaVulkan
RENDERTHREAD_SKIA_TESTS - Runs SkiaGL and SkiaVulkan
RENDERTHREAD_OPENGL_TESTS - Runs OpenGL

Test: manual running of hwui_unit_tests

Change-Id: Ia7420ee7a38803a15e2d58394d14b38cae8208d3
diff --git a/libs/hwui/tests/unit/SkiaRenderPropertiesTests.cpp b/libs/hwui/tests/unit/SkiaRenderPropertiesTests.cpp
index e7171c8..92d9d3d 100644
--- a/libs/hwui/tests/unit/SkiaRenderPropertiesTests.cpp
+++ b/libs/hwui/tests/unit/SkiaRenderPropertiesTests.cpp
@@ -73,7 +73,7 @@
 
 }
 
-RENDERTHREAD_TEST(RenderNodeDrawable, renderPropClipping) {
+TEST(RenderNodeDrawable, renderPropClipping) {
     testProperty([](RenderProperties& properties) {
         properties.setClipToBounds(true);
         properties.setClipBounds(android::uirenderer::Rect(10, 20, 300, 400));
@@ -83,7 +83,7 @@
     });
 }
 
-RENDERTHREAD_TEST(RenderNodeDrawable, renderPropRevealClip) {
+TEST(RenderNodeDrawable, renderPropRevealClip) {
     testProperty([](RenderProperties& properties) {
         properties.mutableRevealClip().set(true, 50, 50, 25);
     }, [](const SkCanvas& canvas) {
@@ -98,7 +98,7 @@
     });
 }
 
-RENDERTHREAD_TEST(RenderNodeDrawable, renderPropOutlineClip) {
+TEST(RenderNodeDrawable, renderPropOutlineClip) {
     testProperty([](RenderProperties& properties) {
         properties.mutableOutline().setShouldClip(true);
         properties.mutableOutline().setRoundRect(10, 20, 30, 40, 5.0f, 0.5f);
@@ -114,7 +114,7 @@
     });
 }
 
-RENDERTHREAD_TEST(RenderNodeDrawable, renderPropTransform) {
+TEST(RenderNodeDrawable, renderPropTransform) {
     testProperty([](RenderProperties& properties) {
         properties.setLeftTopRightBottom(10, 10, 110, 110);