ART: Add GetClassLoaderClasses

Add support for GetClassLoaderClasses, extracting all classes a
given classloader initiated. Add test.

Bug: 31684578
Test: m test-art-host-run-test-912-classes
Change-Id: I0aba27fb1674baf1263c0a19dc2dcce7af013760
diff --git a/test/912-classes/expected.txt b/test/912-classes/expected.txt
index 44c861a..a95a465 100644
--- a/test/912-classes/expected.txt
+++ b/test/912-classes/expected.txt
@@ -43,3 +43,19 @@
 class [Ljava.lang.String; null
 interface Main$InfA dalvik.system.PathClassLoader
 class $Proxy0 dalvik.system.PathClassLoader
+
+boot <- src <- src-ex (A,B)
+912-classes-ex.jar+ -> 912-classes.jar+ -> 
+[class A, class B, class java.lang.Object]
+912-classes.jar+ -> 
+[class B, class java.lang.Object]
+
+boot <- src (B) <- src-ex (A, List)
+912-classes-ex.jar+ -> 912-classes.jar+ -> 
+[class A, class java.lang.Object, interface java.util.List]
+912-classes.jar+ -> 
+[class B, class java.lang.Object]
+
+boot <- src+src-ex (A,B)
+912-classes.jar+ -> 
+[class A, class B, class java.lang.Object]