Upcoming metadata changes in V8 7.4

[cjihrig]

The V8 7.4 update requires the following adjustments to the postmortem debugging metadata constants:

• v8dbg_class_FixedTypedArrayBase__external_pointer__Object
  • Type changed in v8/v8@f70bb59#diff-f3f182b0510ba2ee39ae87e421ff110b.
  • Use v8dbg_class_FixedTypedArrayBase__external_pointer__uintptr_t
• v8dbg_class_JSArrayBuffer__backing_store__Object and v8dbg_class_JSArrayBuffer__byte_length__Object
  • Type changed in v8/v8@f70bb59#diff-f3f182b0510ba2ee39ae87e421ff110b.
  • Use v8dbg_class_JSArrayBuffer__backing_store__uintptr_t and v8dbg_class_JSArrayBuffer__byte_length__size_t
• v8dbg_class_Map__raw_instance_descriptors__DescriptorArray
  • Changed in v8/v8@d7b08b6#diff-59788e25dc5196c356894d5e1fac6425
  • New constant added to V8: v8dbg_class_Map__instance_descriptors_offset
• v8dbg_PointerSizeLog2 (done in src: use new SystemPointerSize constant #300)
  • Changed in v8/v8@46d1986#diff-f3f182b0510ba2ee39ae87e421ff110b
  • Refs: https://bugs.chromium.org/p/v8/issues/detail?id=8477
  • Use new constants: v8dbg_SystemPointerSize, v8dbg_SystemPointerSizeLog2,
    v8dbg_TaggedSize, and v8dbg_TaggedSizeLog2

Refs: nodejs/node#26685

[mmarchini]

Related change: v8/v8@9a149af

(I should start to update our Node.js postmortem tests when I use new constants here 😛 )

[mmarchini]

This seems related as well: https://chromium-review.googlesource.com/c/v8/v8/+/1278014