Make missing DEX2OAT_TARGET_INSTRUCTION_SET_FEATURES an error

Change-Id: I3ca23e4db80c8ab8a86da6408cf38daccd4cfaf1
diff --git a/runtime/common_test.h b/runtime/common_test.h
index 79fa680..643ed1d 100644
--- a/runtime/common_test.h
+++ b/runtime/common_test.h
@@ -423,13 +423,9 @@
 
       InstructionSet instruction_set = kNone;
 
-      // take the default set of instruction features from the build if present
+      // Take the default set of instruction features from the build.
       InstructionSetFeatures instruction_set_features =
-#ifdef ART_DEFAULT_INSTRUCTION_SET_FEATURES
-        ParseFeatureList(STRINGIFY(ART_DEFAULT_INSTRUCTION_SET_FEATURES));
-#else
-        ParseFeatureList("default");
-#endif
+          ParseFeatureList(STRINGIFY(ART_DEFAULT_INSTRUCTION_SET_FEATURES));
 
 #if defined(__arm__)
       instruction_set = kThumb2;