staticdata: Restore custom MethodTable dispatch status (#62170)
When a package image is loaded, methods in a worklist-owned custom
`@MethodTable` used to be restored in place as internal typemap entries,
skipping `jl_method_table_activate` and coming back with a cleared
`dispatch_status` (no
`METHOD_SIG_LATEST_WHICH`/`METHOD_SIG_LATEST_ONLY`). This made
`queue_external_cis` drop foreign `CodeInstance`s cached on such methods
during downstream precompilation, and made on-load edge revalidation
treat calls to them as invalidated, so GPUCompiler-style compilation
caches never survived a package image when the overlay method and the
cached code live in the same package.
Fix this by treating all custom method tables as external:
method tables owned by the worklist are now serialized
without their contents (their defs and dispatch caches are dropped), and
all of their still-valid methods are collected as extext methods, so
`jl_add_methods` / `jl_activate_methods` re-add and re-activate them on
load through the same batched, `allow_new_worlds`-gated path used for
methods extending tables owned by other modules. Activation restores the
dispatch fast-path bits.
x-ref: #58291, which added the on-load edge revalidation gated on these
dispatch bits, but only restored them for methods activated through the
external path.
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
