inference-directed codegen via CodeInstance edges and typeinf_ext_toplevel APIs (#56880)
This is building upon the many efforts around using CodeInstance
everywhere (especially as the return value from jl_type_infer and the
input format to edges) by moving a lot of hard-coded algorithms that
were previously in C (such as `recursive_compile_graph` and
`jl_ci_cache_lookup`), and which were therefore previously also slightly
broken (especially with concurrent environments), into Julia's
Compiler.jl code, where we can most likely maintain them much better
going forward. See descriptions in the individual commits for some of
the specifics of the changes and fixes, and how to change existing code
to use these API correctly. In followup stages, most code relevant to
precompile_utils, trim, and even the allocation-checker should consider
being moved into Julia also now, since being written in C/C++ is
currently providing negative value for maintaining those, and the change
in the API boundary should now make that additional conversion easier.
Gives a considerably smaller system image, despite having more code, by
being better algorithms which avoid allocating permanent garbage: 155 MB
-> 147MB in `.text`
Makes a slightly larger Pkg.ji file cache, hopefully mainly due to being
more strategic about what code is compiled (because that logic is mostly
now in Julia instead of C), as it appear to have both inferred and
compiled about 10% more code according to high level analysis of it:
$ du -sh usr/share/julia/compiled/v1.12/
237M # on PR
222M # on master
julia
ed2cb490 - inference-directed codegen via CodeInstance edges and typeinf_ext_toplevel APIs (#56880)
