[Sema] NFC: Minor foldSequence simplification

Author: hamishknight

lib/Sema/TypeCheckExpr.cpp

@@ -418,12 +418,8 @@ static Expr *foldSequence(DeclContext *DC,
     }
 
     // Pull out the next binary operator.
-    Op op2{S[0], TypeChecker::lookupPrecedenceGroupForInfixOperator(
-                     DC, S[0], /*diagnose=*/true)};
-
-    // If the second operator's precedence is lower than the
-    // precedence bound, break out of the loop.
-    if (!precedenceBound.shouldConsider(op2.precedence)) break;
+    Op op2 = getNextOperator();
+    if (!op2) break;
 
     // If we're missing precedence info for either operator, treat them
     // as non-associative.