Revert "Unload oat files"

Tentative, will monitor bots if flakiness is fixed.

Bug: 22720414

This reverts commit 18656fefc7e68e2549a8fa93455074d359d1efa8.

Change-Id: I53b645b73207ccd21cad6ddac1de483bcc158794
diff --git a/runtime/common_runtime_test.cc b/runtime/common_runtime_test.cc
index b6b5141..56c5d1a 100644
--- a/runtime/common_runtime_test.cc
+++ b/runtime/common_runtime_test.cc
@@ -42,7 +42,6 @@
 #include "mirror/class-inl.h"
 #include "mirror/class_loader.h"
 #include "mem_map.h"
-#include "native/dalvik_system_DexFile.h"
 #include "noop_compiler_callbacks.h"
 #include "os.h"
 #include "primitive.h"
@@ -517,7 +516,7 @@
           mirror::LongArray* long_array = cookie_field->GetObject(dex_file)->AsLongArray();
           DCHECK(long_array != nullptr);
           int32_t long_array_size = long_array->GetLength();
-          for (int32_t j = kDexFileIndexStart; j < long_array_size; ++j) {
+          for (int32_t j = 0; j < long_array_size; ++j) {
             const DexFile* cp_dex_file = reinterpret_cast<const DexFile*>(static_cast<uintptr_t>(
                 long_array->GetWithoutChecks(j)));
             if (cp_dex_file == nullptr) {