[vm] Enable mirrors in product mode. Allows building a product mode SDK.

runtime/lib/mirrors.cc

Index: runtime/lib/mirrors.cc
diff --git a/runtime/lib/mirrors.cc b/runtime/lib/mirrors.cc
index 9e2a1ddf04d455d805aa9c7c470309c8ce9f7070..b0199f6e969032656bd05a56d87e1d3aa491177e 100644
--- a/runtime/lib/mirrors.cc
+++ b/runtime/lib/mirrors.cc
@@ -20,7 +20,7 @@
 
 namespace dart {
 
-#if !defined(PRODUCT) && !defined(DART_PRECOMPILED_RUNTIME)
+#if !defined(DART_PRECOMPILED_RUNTIME)
 
 #define PROPAGATE_IF_MALFORMED(type)                                           \
   if (type.IsMalformed()) {                                                    \
@@ -2113,6 +2113,6 @@ DEFINE_NATIVE_ENTRY(TypeMirror_subtypeTest, 2) {
   return Bool::Get(a.IsSubtypeOf(b, NULL, NULL, Heap::kNew)).raw();
 }
 
-#endif  // !PRODUCT && !DART_PRECOMPILED_RUNTIME
+#endif  // !DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart