Dump out types for expressions, and handle typedefs nicely.

This allows us to dump:

typedef short S;
int test(S X, long long Y) {
  return X < ((100));
}

as:

typedef short S;

int test(S X, long long Y)
(CompoundStmt 0x2905d40
  (ReturnStmt 0x2905d30
    (BinaryOperator 0x2905d10 'int' '<'
      (ImplicitCastExpr 0x2905d00 'int'
        (DeclRefExpr 0x2905c80 'S':'short' Decl='X' 0x2905c20))
      (ParenExpr 0x2905ce0 'int'
        (ParenExpr 0x2905cc0 'int'
          (IntegerLiteral 0x2905ca0 'int' 100))))))

llvm-svn: 40956