Auto merge of #29600 - mrobinson:layout-2020-args, r=jdm

Have all mach command accept "--with-layout-2020" and "--layout-2020"

Some command accepted one and some the other. This changes makes them all accept both so it's no longer necessary to remember which uses which.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes do not require tests because they change the arguments accepted by mach.

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