Remove the obsolete OverwriteMode optimization.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index 79a5efc44e8e959231394ec2977b3d8427d4e942..b2178fbfd1beb32360214601872c2ea948c292f2 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -268,12 +268,8 @@ MaybeHandle<Code> CodeStub::GetCode(Isolate* isolate, uint32_t key) {
 void BinaryOpICStub::GenerateAheadOfTime(Isolate* isolate) {
   // Generate the uninitialized versions of the stub.
   for (int op = Token::BIT_OR; op <= Token::MOD; ++op) {
-    for (int mode = NO_OVERWRITE; mode <= OVERWRITE_RIGHT; ++mode) {
-      BinaryOpICStub stub(isolate,
-                          static_cast<Token::Value>(op),
-                          static_cast<OverwriteMode>(mode));
-      stub.GetCode();
-    }
+    BinaryOpICStub stub(isolate, static_cast<Token::Value>(op));
+    stub.GetCode();
   }
 
   // Generate special versions of the stub.