[heap] Fix third-party-heap PageFromAddress check in CSA

Use compile-time DCHECK instead of Unreachable().

GenerateRecordWrite is disabled to prevent the use of PageFromAddress
when TPH is enabled.

Another user of PageFromAddress is TrapAllocationMemento, this will
be disabled in https://chromium-review.googlesource.com/c/v8/v8/+/2897326.

Bug: v8:11641
Change-Id: I1393d5ad52695a79750be00f2205648458f9c79d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2909216
Commit-Queue: Wenyu Zhao <wenyu.zhao@anu.edu.au>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74805}

src/builtins/builtins-internal-gen.cc

@@ -345,6 +345,10 @@ class WriteBarrierCodeStubAssembler : public CodeStubAssembler {
 
   void GenerateRecordWrite(RememberedSetAction rs_mode,
                            SaveFPRegsMode fp_mode) {
+    if (V8_DISABLE_WRITE_BARRIERS_BOOL) {
+      Return(TrueConstant());
+      return;
+    }
     switch (rs_mode) {
       case RememberedSetAction::kEmit:
         GenerationalWriteBarrier(fp_mode);

src/codegen/code-stub-assembler.cc

@@ -11236,7 +11236,7 @@ void CodeStubAssembler::TrapAllocationMemento(TNode<JSObject> object,
 }
 
 TNode<IntPtrT> CodeStubAssembler::PageFromAddress(TNode<IntPtrT> address) {
-  if (FLAG_enable_third_party_heap) Unreachable();
+  DCHECK(!V8_ENABLE_THIRD_PARTY_HEAP_BOOL);
   return WordAnd(address, IntPtrConstant(~kPageAlignmentMask));
 }