Revert "[OrderedHashSet] Remove redundant hash to bucket"

This reverts commit 88376a78.

Reason for revert: the number of buckets could change, so we can't cache the value

Original change's description:
> [OrderedHashSet] Remove redundant hash to bucket
> 
> Bug: v8:5717
> Change-Id: I88e1e3089844b0955f0f7a6a792c2e10949a5b18
> Reviewed-on: https://chromium-review.googlesource.com/480927
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44707}

TBR=adamk@chromium.org,cbruni@chromium.org,gsathya@chromium.org,v8-reviews@googlegroups.com
# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: I4d42021a1d1f5bc069b3787efc828761098038e0
Reviewed-on: https://chromium-review.googlesource.com/483903Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44760}

src/objects.cc

@@ -18868,8 +18868,7 @@ bool OrderedHashTable<Derived, entrysize>::HasKey(Handle<Derived> table,
 Handle<OrderedHashSet> OrderedHashSet::Add(Handle<OrderedHashSet> table,
                                            Handle<Object> key) {
   int hash = Object::GetOrCreateHash(table->GetIsolate(), key)->value();
-  int bucket = table->HashToBucket(hash);
-  int previous_entry = table->HashToEntry(hash, bucket);
+  int previous_entry = table->HashToEntry(hash);
   int entry = previous_entry;
   // Walk the chain of the bucket and try finding the key.
   while (entry != kNotFound) {
@@ -18881,6 +18880,7 @@ Handle<OrderedHashSet> OrderedHashSet::Add(Handle<OrderedHashSet> table,
 
   table = OrderedHashSet::EnsureGrowable(table);
   // Read the existing bucket values.
+  int bucket = table->HashToBucket(hash);
   int nof = table->NumberOfElements();
   // Insert a new entry at the end,
   int new_entry = nof + table->NumberOfDeletedElements();

src/objects/hash-table.h

@@ -410,18 +410,17 @@ class OrderedHashTable : public FixedArray {
 
   int HashToBucket(int hash) { return hash & (NumberOfBuckets() - 1); }
 
-  int HashToEntry(int hash, int bucket) {
+  int HashToEntry(int hash) {
+    int bucket = HashToBucket(hash);
     Object* entry = this->get(kHashTableStartIndex + bucket);
     return Smi::cast(entry)->value();
   }
 
   int KeyToFirstEntry(Isolate* isolate, Object* key) {
-    Object* hash_obj = key->GetHash();
+    Object* hash = key->GetHash();
     // If the object does not have an identity hash, it was never used as a key
-    if (hash_obj->IsUndefined(isolate)) return kNotFound;
-    int hash = Smi::cast(hash_obj)->value();
-    int bucket = HashToBucket(hash);
-    return HashToEntry(hash, bucket);
+    if (hash->IsUndefined(isolate)) return kNotFound;
+    return HashToEntry(Smi::cast(hash)->value());
   }
 
   int NextChainEntry(int entry) {