Add unit tests for invalid transfomations in Layer

This CL extracts common set up logic for layer related tests to another
file so that it can be shared among tests.

Bug: 210837722
Test: atest libsurfaceflinger_unittest
Change-Id: I9fb08ad164d57369f503a35eca907393b1969547
diff --git a/services/surfaceflinger/tests/unittests/Android.bp b/services/surfaceflinger/tests/unittests/Android.bp
index 58cd7ba..1eea023 100644
--- a/services/surfaceflinger/tests/unittests/Android.bp
+++ b/services/surfaceflinger/tests/unittests/Android.bp
@@ -89,6 +89,8 @@
         "LayerHistoryTest.cpp",
         "LayerInfoTest.cpp",
         "LayerMetadataTest.cpp",
+        "LayerTest.cpp",
+        "LayerTestUtils.cpp",
         "MessageQueueTest.cpp",
         "SurfaceFlinger_CreateDisplayTest.cpp",
         "SurfaceFlinger_DestroyDisplayTest.cpp",