fix perf regression from not specializing on iterate on tuples

[KristofferC]

Fixes #28764 (comment).

cc @haampie

perf_setindex!(A, val, inds) = setindex!(A, val, inds...)

using BenchmarkTools
s = 2
A = rand(Float64, ntuple(one, s)...)
y = one(eltype(A))
i = length(A)
@btime perf_setindex!($(fill!(A, y)), $y, $i)

Before:

1.308 μs (8 allocations: 336 bytes)

After:

570.000 ns (8 allocations: 336 bytes)

[KristofferC]

@nanosoldier runbenchmarks("array", vs = ":master")

[nanosoldier]

Your benchmark job has completed - possible performance regressions were detected. A full report can be found here. cc @ararslan

[vtjnash]

This is strange—inference isn’t supposed to look at this flag. It would be helpful to understand what inlining decisions got made and why, as this might be indicating a deeper problem.

[KristofferC]

Since 1.0.1 is imminent and this fixes a regression (just restores things back to how things where not too long ago). I'll merge this so we can get 1.0.1 out and open an issue so we can continue tracking this.