Reenable function source fingerprint checks. Added checks to MethodRecognizer.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 15218)
+++ runtime/vm/object.cc	(working copy)
@@ -4215,12 +4215,25 @@
     result = 31 * result + val;
     tokens_iterator.Advance();
   }
-  result = result & ((static_cast<intptr_t>(1) << 30) - 1);
+  result = result & ((static_cast<uint32_t>(1) << 31) - 1);
   ASSERT(result <= static_cast<uint32_t>(kMaxInt32));
   return result;
 }
 
 
+bool Function::CheckSourceFingerprint(intptr_t fp) const {
+  if (SourceFingerprint() != fp) {
+    OS::Print("FP mismatch while recogbnizing method %s:"
+      " expecting %"Pd" found %d\n",
+      ToFullyQualifiedCString(),
+      fp,
+      SourceFingerprint());
+    return false;
+  }
+  return true;
+}
+
+
 const char* Function::ToCString() const {
   const char* static_str = is_static() ? " static" : "";
   const char* abstract_str = is_abstract() ? " abstract" : "";