Rollup merge of #136339 - veera-sivarajan:ignore-arm-unknown-headers, r=jieyouxu

CompileTest: Add Directives to Ignore `arm-unknown-*` Targets

In  #134626, I want to ignore `arm-unknown-*` targets because the LLVM IR for those looks very different compared to other targets: https://rust.godbolt.org/z/ssYMhdv4x.

I can use `ignore-arm` but, I think, it would exclude large number of Apple devices.

So this PR adds a few directives to ignore `arm-unknown-*` targets specifically.

Author: matthiaskrgr