Revert^8 "Make sure that const-class linkage is preserved."

Replaced two ReaderMutexLocks with WriterMutexLocks.
Removed some unnecessary debugging output.

Test: m test-art-host
Bug: 30627598
Original-Change-Id: Ie9b721464b4e9a5dcce8df8095548e983bba1fe8

This reverts commit 2c8c6b63da6ecb2ac701cc30f9b4fa4a8eea5cc8.

Change-Id: I3a1aeecf64e4b202cef61cceb248d48106a2f4a6
diff --git a/compiler/image_writer.h b/compiler/image_writer.h
index 24fad46..c537483 100644
--- a/compiler/image_writer.h
+++ b/compiler/image_writer.h
@@ -50,6 +50,7 @@
 }  // namespace space
 }  // namespace gc
 
+class ClassLoaderVisitor;
 class ClassTable;
 
 static constexpr int kInvalidFd = -1;
@@ -373,6 +374,9 @@
   void ComputeLazyFieldsForImageClasses()
       REQUIRES_SHARED(Locks::mutator_lock_);
 
+  // Visit all class loaders.
+  void VisitClassLoaders(ClassLoaderVisitor* visitor) REQUIRES_SHARED(Locks::mutator_lock_);
+
   // Remove unwanted classes from various roots.
   void PruneNonImageClasses() REQUIRES_SHARED(Locks::mutator_lock_);
 
@@ -588,7 +592,8 @@
   class FixupVisitor;
   class GetRootsVisitor;
   class NativeLocationVisitor;
-  class NonImageClassesVisitor;
+  class PruneClassesVisitor;
+  class PruneClassLoaderClassesVisitor;
   class VisitReferencesVisitor;
 
   DISALLOW_COPY_AND_ASSIGN(ImageWriter);