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.cc b/runtime/utils.cc
index 52cdcc1..4d49809 100644
--- a/runtime/utils.cc
+++ b/runtime/utils.cc
@@ -1236,7 +1236,7 @@
     return false;
   }
   std::string cache_file(&location[1]);  // skip leading slash
-  if (!EndsWith(location, ".dex") && !EndsWith(location, ".art")) {
+  if (!EndsWith(location, ".dex") && !EndsWith(location, ".art") && !EndsWith(location, ".oat")) {
     cache_file += "/";
     cache_file += DexFile::kClassesDex;
   }