Revert^3 "Disable check that no oat libraries are loaded."""

This reverts commit e9fa8db2edd469c5dc92dd42ab0e9e80d345dc1f.

Reason for revert: Fails test 677-fsi on target

 Abort message: 'Check failed: LocationIsOnSystem(oat_file->GetLocation().c_str()) /data/art-test/core-core-libart-testdex.oat'

Change-Id: I7045283ae8af24218798a42e7f66ca8ab4ca3dd2
diff --git a/runtime/oat_file_manager.cc b/runtime/oat_file_manager.cc
index 2642cd8..b03551b 100644
--- a/runtime/oat_file_manager.cc
+++ b/runtime/oat_file_manager.cc
@@ -645,12 +645,7 @@
 void OatFileManager::SetOnlyUseSystemOatFiles(bool assert_no_files_loaded) {
   ReaderMutexLock mu(Thread::Current(), *Locks::oat_file_manager_lock_);
   if (assert_no_files_loaded) {
-    // Make sure all files that were loaded up to this point are on /system.
-    if (kIsTargetBuild) {
-      for (const std::unique_ptr<const OatFile>& oat_file : oat_files_) {
-        CHECK(LocationIsOnSystem(oat_file->GetLocation().c_str())) << oat_file->GetLocation();
-      }
-    }
+    CHECK_EQ(oat_files_.size(), GetBootOatFiles().size());
   }
   only_use_system_oat_files_ = true;
 }