Change ClassStatus to fit into 4 bits.

In preparation for extending the type check bit string from
24 to 28 bits, rewrite ClassStatus to fit into 4 bits. Also
perform a proper cleanup of the ClassStatus, i.e. change it
to an enum class, remove the "Status" word from enumerator
names, replace "Max" with "Last" in line with other
enumerations and remove aliases from mirror::Class.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Test: Pixel 2 XL boots.
Test: testrunner.py --target --optimizing
Bug: 64692057
Bug: 65318848
Change-Id: Iec1610ba5dac2c527b36c12819f132e1a77f2d45
diff --git a/runtime/transaction_test.cc b/runtime/transaction_test.cc
index 304017e..0bad548 100644
--- a/runtime/transaction_test.cc
+++ b/runtime/transaction_test.cc
@@ -66,7 +66,7 @@
     class_linker_->VerifyClass(soa.Self(), h_klass);
     ASSERT_TRUE(h_klass->IsVerified());
 
-    mirror::Class::Status old_status = h_klass->GetStatus();
+    ClassStatus old_status = h_klass->GetStatus();
     LockWord old_lock_word = h_klass->GetLockWord(false);
 
     Runtime::Current()->EnterTransactionMode();