fix Sockets type stability issues

[JeffBezanson]

fixes #59397

[topolarity]

Probably worth adding using Sockets (and more?) to our JLL --trim example.

Eventually we can split this out into its own example, but better to have the coverage until that CI is added.

[JeffBezanson]

OK I added a test, and separated out the hello test for minimum executable size from tests that various things are trimmable, so that can grow arbitrarily large.

[nsajko]

CI for PR #59442 segfaults on this line:

[1246] signal 11 (1): Segmentation fault
in expression starting at none:0
speccache_eq at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:144 [inlined]
speccache_eq at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:136
jl_smallintset_lookup at /cache/build/tester-demeter6-13/julialang/julia-master/src/smallintset.c:137
jl_specializations_get_linfo_ at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:183
cache_method at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:1585
jl_mt_assoc_by_type at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:1867
jl_lookup_generic_ at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:4168 [inlined]
ijl_apply_generic at /cache/build/tester-demeter6-13/julialang/julia-master/src/gf.c:4194
jl_apply at /cache/build/tester-demeter6-13/julialang/julia-master/src/julia.h:2382 [inlined]
jl_uv_call_close_callback at /cache/build/tester-demeter6-13/julialang/julia-master/src/jl_uv.c:171
jl_uv_closeHandle at /cache/build/tester-demeter6-13/julialang/julia-master/src/jl_uv.c:191 [inlined]
jl_uv_closeHandle at /cache/build/tester-demeter6-13/julialang/julia-master/src/jl_uv.c:175
uv__finish_close at /workspace/srcdir/libuv/src/unix/core.c:342
uv__run_closing_handles at /workspace/srcdir/libuv/src/unix/core.c:356
uv_run at /workspace/srcdir/libuv/src/unix/core.c:445
ijl_process_events at /cache/build/tester-demeter6-13/julialang/julia-master/src/jl_uv.c:397
process_events; at ./libuv.jl:133 [inlined]
wait at ./task.jl:1188
#wait#401 at ./condition.jl:141
wait; at ./condition.jl:136 [inlined]
wait_connected at /cache/build/tester-demeter6-13/julialang/julia-master/usr/share/julia/stdlib/v1.13/Sockets/src/Sockets.jl:539
connect; at /cache/build/tester-demeter6-13/julialang/julia-master/usr/share/julia/stdlib/v1.13/Sockets/src/Sockets.jl:579 [inlined]
connect at /cache/build/tester-demeter6-13/julialang/julia-master/usr/share/julia/stdlib/v1.13/Sockets/src/Sockets.jl:564
main at /cache/build/builder-amdci4-5/julialang/julia-master/test/trimming/trimmability.jl:42
_main at /cache/build/builder-amdci4-5/julialang/julia-master/usr/share/julia/juliac/juliac-buildscript.jl:33
main at /cache/build/builder-amdci4-5/julialang/julia-master/usr/bin/trimmability (unknown line)
__libc_start_main at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
unknown function (ip: 0x402338) at /workspace/srcdir/glibc-2.17/csu/../sysdeps/x86_64/start.S
Allocations: 1 (Pool: 1; Big: 0); GC: 0

Perhaps this is flaky?

CI link:

• https://buildkite.com/julialang/julia-master/builds/50301/steps/canvas?sid=01990f94-ac54-4864-9b1a-cd113ad3c427#01990f94-ac86-4a66-b6f4-f1a96386fafd/1042-1104

[vtjnash]

I would suggest reverting since this PR broke CI, but there isn't really anything to revert in the source, it is just adding a broken test. Perhaps we can just disable the test until Jeff can fix it?