[wasm] Fix allocation of win64 crashpad data

Ensure that the "padding" (actually needed for crashpad) is allocated
at the beginning of the new code space.

R=ahaas@chromium.org

Bug: v8:9477
Change-Id: I44b9e9feb559788e286fd5c57df90db7cf7f5340
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1803650
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63790}

src/wasm/wasm-code-manager.cc

@@ -1199,9 +1199,9 @@ void NativeModule::AddCodeSpace(base::AddressRegion region) {
       !implicit_alloc_disabled) {
     size_t size = Heap::GetCodeRangeReservedAreaSize();
     DCHECK_LT(0, size);
-    Vector<byte> padding = code_allocator_.AllocateForCode(this, size);
-    CHECK(region.contains(reinterpret_cast<Address>(padding.begin()),
-                          padding.size()));
+    Vector<byte> padding =
+        code_allocator_.AllocateForCodeInRegion(this, size, region);
+    CHECK_EQ(reinterpret_cast<Address>(padding.begin()), region.begin());
   }
 #endif  // V8_OS_WIN64