Unoptimal inference when function has error in a implicit return

[gbaraldi]

While investigating some type instabilities in Pkg code specifically

	code_typed(Pkg.Artifacts.:(var"#ensure_artifact_installed#21"), (Base.BinaryPlatforms.Platform, Bool, Bool, IO, typeof(Pkg.Artifacts.ensure_artifact_installed), String, Dict, String), optimize=true)

the #21 might not be correct but it's the kwcall done in code_typed(Core.kwcall, (@NamedTuple{platform::Base.BinaryPlatforms.Platform}, typeof(Pkg.Artifacts.ensure_artifact_installed), String, Dict{String, Any}, String))
this code has a unstable return type because inference isn't able to succeed in realising that a call to error always throws

│     %486 = Base.not_int(%485)::Bool
└────        goto #107 if not %486
106 ─        goto #97
107 ┄ %489 = φ (#105 => %453, #96 => %405)::Any
│     %490 = Pkg.Artifacts.error(%489)::Any
└────        return %490
108 ─ %492 = π (%2, Base.SHA1)
│     %493 = Pkg.Artifacts.artifact_path::typeof(Artifacts.artifact_path)
│     %494 = invoke Artifacts.:(var"#artifact_path#7")(true::Bool, %493::typeof(Artifacts.artifact_path), %492::Base.SHA1)::String
└────        return %494

[KristofferC]

Fixed by #49260 I guess

[aviatesk]

It turns out that this is because Pkg.jl set @max_methods 2 globally: https://github.com/JuliaLang/Pkg.jl/blob/00aa38cb3a85e200c4bd19efef3a15e32e192a8f/src/Pkg.jl#L5-L7

I have a potential solution in my mind, but it looks like it won't require merging #49260.

[aviatesk]

See #54086.