generic size: avoid method static parameters and abstract type assert

[nsajko]

The generic method size(::AbstractArray, ::Any) currently has:

• method static parameters

• an abstract type assert (::Integer) in the method body

PR #59442 aims to make this generic method be used for Array and Memory, by deleting the more specific methods.

It is my understanding that method static parameters and abstract type asserts can cause performance issues, when they're not optimized out, which happens when the argument types are not concretely inferred.

So I'm putting up this PR, which eliminates the method static parameters and the typeassert, to prevent any possible regressions from PR #59442.

Another thing that is necessary for preserving good abstract inference is to convert the index argument to Int before using it. This is correct as there can't be more than typemax(Int) dimensions anyway (the N type parameter to AbstractArray is an Int value).

[nsajko]

Indeed, this PR is a prerequisite for PR #59442. Otherwise three of these effect inference tests fail:

julia/Compiler/test/effects.jl

Lines 792 to 797 in cdd4ac5

	let effects = Base.infer_effects(size, (Array,Int))
	@test Compiler.is_consistent_if_inaccessiblememonly(effects)
	@test Compiler.is_effect_free(effects)
	@test !Compiler.is_nothrow(effects)
	@test Compiler.is_terminates(effects)
	end

[nsajko]

bump

[nsajko]

ping

[vtjnash]

I don't like this. It changes clear code into a mess. Changing to simplified code like this would be okay though:

function size(t::AbstractArray, dim)
    d = Int(dim)::Int
    s = size(t)
    d <= length(s) ? s[d] : 1
end