Revert "[wasm][gc] Reenable discarding system pages"

This reverts commit 200a594a.

Reason for revert: Fails on windows: https://ci.chromium.org/p/v8/builders/ci/V8%20Win32%20-%20debug/20310

Original change's description:
> [wasm][gc] Reenable discarding system pages
> 
> On windows, the range to be discarded needs to be split by the
> reservations, analogous to committing. This CL reuses the same logic,
> and reenables discarding pages on all platforms.
> 
> R=​mstarzinger@chromium.org
> 
> Bug: v8:8217
> Change-Id: I11716d6381f765bdfe4cf48502b5cdc1f42cf8ab
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1611682
> Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#61526}

TBR=mstarzinger@chromium.org,clemensh@chromium.org

Change-Id: I35bfbec222c4ba9e7b5990c02d004f7247b28131
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:8217
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1611802Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61527}

src/wasm/wasm-code-manager.cc

@@ -599,12 +599,9 @@ void WasmCodeAllocator::FreeCode(Vector<WasmCode* const> codes) {
         std::min(RoundDown(merged_region.end(), commit_page_size),
                  RoundUp(region.end(), commit_page_size));
     if (discard_start >= discard_end) continue;
-    // TODO(clemensh): Update committed_code_space_ counter.
-    for (base::AddressRegion split_range : SplitRangeByReservationsIfNeeded(
-             {discard_start, discard_end - discard_start}, owned_code_space_)) {
-      allocator->DiscardSystemPages(
-          reinterpret_cast<void*>(split_range.begin()), split_range.size());
-    }
+    // TODO(clemensh): Reenable after fixing https://crbug.com/960707.
+    // allocator->DiscardSystemPages(reinterpret_cast<void*>(discard_start),
+    //                               discard_end - discard_start);
   }
 }