Rollup merge of #70978 - RalfJung:compiletest-flags, r=Mark-Simulacrum
Rollup merge of #70978 - RalfJung:compiletest-flags, r=Mark-Simulacrum

compiletest: let config flags overwrite -A unused

Cc https://github.com/laumann/compiletest-rs/issues/216

aidancully/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust