Reenable function source fingerprint checks. Added checks to MethodRecognizer.

runtime/vm/intrinsifier.cc

Index: runtime/vm/intrinsifier.cc
===================================================================
--- runtime/vm/intrinsifier.cc	(revision 15218)
+++ runtime/vm/intrinsifier.cc	(working copy)
@@ -95,14 +95,14 @@
 
 
 static bool CheckFingerprint(const Function& function, intptr_t fp) {
-  /*if (function.SourceFingerprint() != fp) {
+  if (function.SourceFingerprint() != fp) {
     OS::Print("FP mismatch while intrinsifying %s:"
       " expecting %"Pd" found %d\n",
       function.ToFullyQualifiedCString(),
       fp,
       function.SourceFingerprint());
-    return true;
-  } */
+    return false;
+  }
   return true;
 }