Remove the first_right_arg hack for HMod.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 8d73c1e51976f7cd4b2e849e1faf5f9c8930f94c..e980ecc5a9116fa1f05fd1447e773e162c6d1ed6 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -8717,9 +8717,24 @@ HValue* HGraphBuilder::BuildBinaryOperation(
       case Token::MUL:
         instr = AddUncasted<HMul>(left, right);
         break;
-      case Token::MOD:
-        instr = AddUncasted<HMod>(left, right, fixed_right_arg);
+      case Token::MOD: {
+        if (fixed_right_arg.has_value) {
+          if (right->IsConstant()) {
+            ASSERT_EQ(fixed_right_arg.value,
+                      HConstant::cast(right)->Integer32Value());
+          } else {
+            HConstant* fixed_right = Add<HConstant>(
+                static_cast<int>(fixed_right_arg.value));
+            IfBuilder if_same(this);
+            if_same.If<HCompareNumericAndBranch>(right, fixed_right, Token::EQ);
+            if_same.Then();
+            if_same.ElseDeopt("Unexpected RHS of binary operation");
+            right = fixed_right;
+          }
+        }
+        instr = AddUncasted<HMod>(left, right);
         break;
+      }
       case Token::DIV:
         instr = AddUncasted<HDiv>(left, right);
         break;