ART: Use core image to speed up some gtests.

Host timing of
  art_compiler_tests --no_isolate --gtest_filter='<pattern>'
for different patterns:
  "ms total"                    before after
  LoadStoreEliminationTest*      16945  4750
  LoadStoreAnalysisTest*          2647   689
  ReferenceTypePropagationTest*  13542  3929
  InstructionSimplifierTest*      1452   406

Host timing of
  art_runtime_tests --no_isolate --gtest_filter='<pattern>'
for different patterns:
  "ms total"                    before after
  RegType*Test*                   2976  1675
  DexCacheTest*                    265    74
  JavaVmExtTest*                   785   230

Host timing of
  art_libartbase_tests --no_isolate --gtest_filter='<pattern>'
for different patterns:
  "ms total"                    before after
  FlagsTests*                      691   214

Host timing of
  art_dex2oat_tests --no_isolate --gtest_filter='<pattern>'
for different patterns:
  "ms total"                    before after
  VerifierDepsTest*               3567   874

Test: m test-art-host-gtest
Change-Id: I20df90e3d38aaa286e22ba070c7845bcb09e3bca
diff --git a/runtime/common_runtime_test.cc b/runtime/common_runtime_test.cc
index 4eb3408..3f643e8 100644
--- a/runtime/common_runtime_test.cc
+++ b/runtime/common_runtime_test.cc
@@ -71,7 +71,11 @@
 static bool unstarted_initialized_ = false;
 
 CommonRuntimeTestImpl::CommonRuntimeTestImpl()
-    : class_linker_(nullptr), java_lang_dex_file_(nullptr) {
+    : class_linker_(nullptr),
+      java_lang_dex_file_(nullptr),
+      boot_class_path_(),
+      callbacks_(),
+      use_boot_image_(false) {
 }
 
 CommonRuntimeTestImpl::~CommonRuntimeTestImpl() {
@@ -94,6 +98,9 @@
 
   options.push_back(std::make_pair(boot_class_path_string, nullptr));
   options.push_back(std::make_pair(boot_class_path_locations_string, nullptr));
+  if (use_boot_image_) {
+    options.emplace_back("-Ximage:" + GetImageLocation(), nullptr);
+  }
   options.push_back(std::make_pair("-Xcheck:jni", nullptr));
   options.push_back(std::make_pair(min_heap_string, nullptr));
   options.push_back(std::make_pair(max_heap_string, nullptr));
@@ -107,7 +114,7 @@
 
   SetUpRuntimeOptions(&options);
 
-  // Install compiler-callbacks if SetupRuntimeOptions hasn't deleted them.
+  // Install compiler-callbacks if SetUpRuntimeOptions hasn't deleted them.
   if (callbacks_.get() != nullptr) {
     options.push_back(std::make_pair("compilercallbacks", callbacks_.get()));
   }