[cleanup] Remove stale comment

DISALLOW_COPY_AND_ASSIGN is no longer in our codebase, and the compilers
mentioned in the comments are (probably) no longer supported.

Bug: v8:12244
Change-Id: I432bd56ca3ddd870be140032f11d94ddb60ce1a9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3171974Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76977}

src/objects/property-descriptor.h

@@ -122,10 +122,6 @@ class PropertyDescriptor {
   Handle<Object> get_;
   Handle<Object> set_;
   Handle<Object> name_;
-
-  // Some compilers (Xcode 5.1, ARM GCC 4.9) insist on having a copy
-  // constructor for std::vector<PropertyDescriptor>, so we can't
-  // DISALLOW_COPY_AND_ASSIGN(PropertyDescriptor); here.
 };
 
 }  // namespace internal