Rollup merge of #144399 - bjorn3:stdlib_tests_separate_packages, r=Mark-Simulacrum

Add a ratchet for moving all standard library tests to separate packages

rust-lang/rust#136642 is the previous PR in this series. See rust-lang/rust#135937 for the rationale of wanting to move all standard library tests to separate packages.

This also fixes std_detect testing on riscv.

Author: matthiaskrgr