LLVMLongName should preserve the return type.

Change-Id: I0a247e1428cc8816f535b0621b1c8b40179161a4
diff --git a/src/compiler_llvm/utils_llvm.cc b/src/compiler_llvm/utils_llvm.cc
index 98d1c7c..2a9ccba 100644
--- a/src/compiler_llvm/utils_llvm.cc
+++ b/src/compiler_llvm/utils_llvm.cc
@@ -50,6 +50,9 @@
       case '[':
         result += "_3";
         break;
+      case ')':
+        result += "_4";
+        break;
       case '/':
         result += "_";
         break;
@@ -88,7 +91,6 @@
 
   std::string signature(MethodHelper(m).GetSignature());
   signature.erase(0, 1);
-  signature.erase(signature.begin() + signature.find(')'), signature.end());
 
   long_name += MangleForLLVM(signature);