Split testutils-appcompat into its own dependency

Rather than have testutils-runtime depend
directly on AppCompat, move those testutils
that rely on AppCompat into their own module
that can be included only by the modules that
need them.

Test: ./gradlew bOS
Change-Id: Id40efb10fd9a36c3010fd613bbe8b9e63605b220
diff --git a/settings.gradle b/settings.gradle
index 9015f91..913bb2d 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -287,6 +287,7 @@
 
 includeProject(":internal-testutils-common", "testutils/testutils-common")
 includeProject(":internal-testutils-runtime", "testutils/testutils-runtime")
+includeProject(":internal-testutils-appcompat", "testutils/testutils-appcompat")
 includeProject(":internal-testutils-espresso", "testutils/testutils-espresso")
 includeProject(":internal-testutils-ktx", "testutils/testutils-ktx")