Make system use patchoat to relocate during runtime.

Change dalvik_system_DexFile.cc so that isDexOptNeededInternal will be
able to indicate that a patchoat is required. Change default of relocate
option to be on.

Bug: 15358152

Change-Id: Ibe92d8b55a24bbf718b0416a21b76e5df7a2de26
diff --git a/runtime/utils_test.cc b/runtime/utils_test.cc
index 7cd5980..d6c90e1 100644
--- a/runtime/utils_test.cc
+++ b/runtime/utils_test.cc
@@ -350,6 +350,8 @@
                GetDalvikCacheFilenameOrDie("/system/framework/core.jar", "/foo").c_str());
   EXPECT_STREQ("/foo/system@framework@boot.art",
                GetDalvikCacheFilenameOrDie("/system/framework/boot.art", "/foo").c_str());
+  EXPECT_STREQ("/foo/system@framework@boot.oat",
+               GetDalvikCacheFilenameOrDie("/system/framework/boot.oat", "/foo").c_str());
 }
 
 TEST_F(UtilsTest, GetSystemImageFilename) {