[InstCombine] Add commuted tests. NFC.

Author: dtcxzyw

llvm/test/Transforms/InstCombine/rem-mul-shl.ll

@@ -385,6 +385,19 @@ define i8 @srem_XY_XZ_with_CY_gt_CZ_drop_nsw(i8 noundef %X) {
   ret i8 %r
 }
 
+define i8 @srem_XY_XZ_with_CY_gt_CZ_drop_nsw_commuted(i8 noundef %X) {
+; CHECK-LABEL: @srem_XY_XZ_with_CY_gt_CZ_drop_nsw_commuted(
+; CHECK-NEXT:    [[BO0:%.*]] = mul nsw i8 [[X:%.*]], 127
+; CHECK-NEXT:    [[BO1:%.*]] = shl nsw i8 [[X]], 7
+; CHECK-NEXT:    [[R:%.*]] = srem i8 [[BO0]], [[BO1]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %BO0 = mul nsw i8 %X, 127
+  %BO1 = shl nsw i8 %X, 7
+  %r = srem i8 %BO0, %BO1
+  ret i8 %r
+}
+
 define i8 @srem_XY_XZ_with_CY_gt_CZ_fail_missing_flag1(i8 %X) {
 ; CHECK-LABEL: @srem_XY_XZ_with_CY_gt_CZ_fail_missing_flag1(
 ; CHECK-NEXT:    [[BO0:%.*]] = mul nuw nsw i8 [[X:%.*]], 10