Auto merge of rust-lang#102458 - JohnTitor:stabilize-instruction-set, r=oli-obk

Stabilize the `instruction_set` feature

Closes rust-lang#74727
FCP is complete on rust-lang#74727 (comment)
r? `@pnkfelix` and/or `@nikomatsakis`
cc `@xd009642`

Signed-off-by: Yuki Okushi <jtitor@2k36.org>

Author: bors