Enable compose kotlinc plugin when depending on the compose runtime

When a module depends on the compose runtime add a -Xplugin argument
to the kotlinc flags that enables the compose compiler plugin.

Bug: 196351110
Test: TestKotlinCompose
Change-Id: I423a3c4d12df42804a24b672a40a165bc8dd165f

java/builder.go

@@ -263,6 +263,7 @@ type javaBuilderFlags struct {
 
 	kotlincFlags     string
 	kotlincClasspath classpath
+	kotlincDeps      android.Paths
 
 	proto android.ProtoFlags
 }