Backports for Julia 1.11.3

[KristofferC]

Backported PRs:

• fix precompile(::MethodInstance) ccall signature #56595
• Revert "Extensions: make loading of extensions independent of what packages are in the sysimage (#52841) #56234

Need manual backport:

• Fix trampoline assembly for build on clang 18 on apple silicon #54634
• rearrange jl_delete_thread to be thread-safe #56097
• inference: fix inference error from constructing invalid TypeVar #56264
• InteractiveUtils.jl: fixes issue where subtypes resolves bindings and causes deprecation warnings  #56306
• loading: clean up more concurrency issues #56329
• irinterp: set IR_FLAG_REFINED for narrowed PhiNodes #56391
• Allow taking Matrix slices without an extra allocation #56236
• lowering: don't reverse handler order in (pop-handler-list ...) #55871

Contains multiple commits, manual intervention needed:

• fix FileWatching designs and add workaround for a stat bug on Apple #55877
• Make String(::Memory) copy #54457
• recommend explicit using Foo: Foo, ... in package code (was: "using considered harmful") #42080
• precompile: fix performance issues with IO #56370

Non-merged PRs with backport label:

• fix jl_mutex_lock deadlock under rr #56644
• subtype: fast path for Type == TypeVar #56640
• precompilepkgs: make the circular dep warning clearer and more informative #56621
• Fix and test lcm([1//2, 1//2]) == 1//1 #56423
• xref UnionAll in the doc string of where #56411
• Fix generate_precompile statement grouping & avoid defining new func #56317
• REPL: complete imports when there are multiple macros before #56281
• also redirect JL_STDERR etc. when redirecting to devnull #55958
• Make threadcall gc safe #55956
• Check for conflicting @ccallable name before JIT registration #55813
• Set stdlib sources as read-only during installation #55534
• propagate the terminal's displaysize to the IOContext used by the REPL #55499
• Allow for generically extracting unannotated string #55458
• Make AnnotateChar equality consider annotations #55457
• isfile_casesensitive fixes on Windows #55220
• propertynames for SVD respects private argument #55169
• tweak how filtering is done for what packages should be precompiled #53957
• prevent code loading from lookin in the versioned environment when building Julia #51479
• More doctests for Sockets and capitalization fix #50813
• improve docs for @inbounds and Base.@propagate_inbounds #50157

[DilumAluthge]

Okay, I now have CI running here.