Rename getResultType() on function and method declarations to getReturnType()

A return type is the declared or deduced part of the function type specified in
the declaration.

A result type is the (potentially adjusted) type of the value of an expression
that calls the function.

Rule of thumb:

  * Declarations have return types and parameters.
  * Expressions have result types and arguments.

llvm-svn: 200082
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index e836e18..18c3ff1 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -3618,7 +3618,7 @@
 
   EvalStmtResult ESR = EvaluateStmt(Result, Info, Body);
   if (ESR == ESR_Succeeded) {
-    if (Callee->getResultType()->isVoidType())
+    if (Callee->getReturnType()->isVoidType())
       return true;
     Info.Diag(Callee->getLocEnd(), diag::note_constexpr_no_return);
   }