[heap] Drop {kMaxWriteUnprotectCounter} limit by one.

R=hpayer@chromium.org
BUG=v8:6792

Change-Id: I0e773a980b76b033e2561c37db1a43ab1b58da0b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1532071Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60429}

src/heap/spaces.h

@@ -407,8 +407,7 @@ class MemoryChunk {
   static const int kPageSize = 1 << kPageSizeBits;
 
   // Maximum number of nested code memory modification scopes.
-  // TODO(6792,mstarzinger): Drop to 3 or lower once WebAssembly is off heap.
-  static const int kMaxWriteUnprotectCounter = 4;
+  static const int kMaxWriteUnprotectCounter = 3;
 
   static Address BaseAddress(Address a) { return a & ~kAlignmentMask; }