[wasm][gc] Temporarily disable discarding pages

The {DiscardSystemPages} call occasionally fails on win32, thus disable
it until the error is found.

R=mstarzinger@chromium.org

Bug: v8:8217, chromium:960707
Change-Id: Idf77dd8e85d3d38cc12a9f4d2db5cc98eb2c7d08
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1601150Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61331}

src/wasm/wasm-code-manager.cc

@@ -1369,8 +1369,9 @@ void NativeModule::FreeCode(Vector<WasmCode* const> codes) {
     Address discard_end = std::min(RoundDown(merged_region.end(), page_size),
                                    RoundUp(region.end(), page_size));
     if (discard_start >= discard_end) continue;
-    allocator->DiscardSystemPages(reinterpret_cast<void*>(discard_start),
-                                  discard_end - discard_start);
+    // TODO(clemensh): Reenable after fixing https://crbug.com/960707.
+    // allocator->DiscardSystemPages(reinterpret_cast<void*>(discard_start),
+    //                               discard_end - discard_start);
   }
 }