Revert^6 "Hash-based dex cache type array."

Fixed ImageWriter to write class table also if it contains
only boot class loader classes. Added a regression test and
added extra checks for debug-build to verify that dex cache
types from app image are also in the class table. Removed
some unnecessary debug output.

Test: 158-app-image-class-table
Bug: 34839984
Bug: 30627598
Bug: 34659969

This reverts commit 0b66d6174bf1f6023f9d36dda8538490b79c2e9f.

Change-Id: I6a747904940c6ebc297f4946feef99dc0adf930c
diff --git a/runtime/class_table.h b/runtime/class_table.h
index 711eae4..79f5aea 100644
--- a/runtime/class_table.h
+++ b/runtime/class_table.h
@@ -144,16 +144,26 @@
       REQUIRES(!lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  // Returns the number of classes in previous snapshots.
+  // Returns the number of classes in previous snapshots defined by `defining_loader`.
   size_t NumZygoteClasses(ObjPtr<mirror::ClassLoader> defining_loader) const
       REQUIRES(!lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  // Returns all off the classes in the lastest snapshot.
+  // Returns all off the classes in the lastest snapshot defined by `defining_loader`.
   size_t NumNonZygoteClasses(ObjPtr<mirror::ClassLoader> defining_loader) const
       REQUIRES(!lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
+  // Returns the number of classes in previous snapshots no matter the defining loader.
+  size_t NumReferencedZygoteClasses() const
+      REQUIRES(!lock_)
+      REQUIRES_SHARED(Locks::mutator_lock_);
+
+  // Returns all off the classes in the lastest snapshot no matter the defining loader.
+  size_t NumReferencedNonZygoteClasses() const
+      REQUIRES(!lock_)
+      REQUIRES_SHARED(Locks::mutator_lock_);
+
   // Update a class in the table with the new class. Returns the existing class which was replaced.
   mirror::Class* UpdateClass(const char* descriptor, mirror::Class* new_klass, size_t hash)
       REQUIRES(!lock_)