[clang][Sema] Remove dead code. NFC

Author: darkbuck

clang/lib/Sema/SemaStmtAttr.cpp

@@ -218,7 +218,6 @@ class CallExprFinder : public ConstEvaluatedExprVisitor<CallExprFinder> {
 
 static Attr *handleNoMergeAttr(Sema &S, Stmt *St, const ParsedAttr &A,
                                SourceRange Range) {
-  NoMergeAttr NMA(S.Context, A);
   CallExprFinder CEF(S, St);
 
   if (!CEF.foundCallExpr() && !CEF.foundAsmStmt()) {