Revert "[turbofan] Properly zero-extend indices on 64-bit architectures."

This reverts commit 6c7c81e0.

Reason for revert: Dependent CL was reverted.

Original change's description:
> [turbofan] Properly zero-extend indices on 64-bit architectures.
> 
> This was an oversight from the previous CL. It doesn't really matter
> with the current code generation pattern, since the upper bits of the
> index will always be zero, but that might change in the future.
> 
> Bug: chromium:225811
> Change-Id: I568a0824cad9ce9b73a56decc15d146c7dc675a1
> Reviewed-on: https://chromium-review.googlesource.com/1174111
> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#55104}

TBR=jarin@chromium.org,bmeurer@chromium.org

Change-Id: Ib344609b0c4734c6512e6be287a5b7f80bc3f603
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:225811
Reviewed-on: https://chromium-review.googlesource.com/1174232Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55109}

src/compiler/effect-control-linearizer.cc

@@ -3759,12 +3759,6 @@ Node* EffectControlLinearizer::LowerLoadDataViewElement(Node* node) {
   Node* index = node->InputAt(2);
   Node* is_little_endian = node->InputAt(3);
 
-  // On 64-bit platforms, we need to feed a Word64 index to the Load and
-  // Store operators.
-  if (machine()->Is64()) {
-    index = __ ChangeUint32ToUint64(index);
-  }
-
   // We need to keep the {buffer} alive so that the GC will not release the
   // ArrayBuffer (if there's any) as long as we are still operating on it.
   __ Retain(buffer);
@@ -3939,12 +3933,6 @@ void EffectControlLinearizer::LowerStoreDataViewElement(Node* node) {
   Node* value = node->InputAt(3);
   Node* is_little_endian = node->InputAt(4);
 
-  // On 64-bit platforms, we need to feed a Word64 index to the Load and
-  // Store operators.
-  if (machine()->Is64()) {
-    index = __ ChangeUint32ToUint64(index);
-  }
-
   // We need to keep the {buffer} alive so that the GC will not release the
   // ArrayBuffer (if there's any) as long as we are still operating on it.
   __ Retain(buffer);