ghc-toolchain followup: Move the remaining toolchain settings to Toolchain
In !9263 we removed almost all `settings-xxx` from the hadrian configuration in favour of reading those settings from the relevant Target description file.
The glaring omissions, that weren't immediately needed for the patch, are:
* [x] `otool`
* [x] `install-name-tool`
* [x] `llc`
* [x] `opt`
* [x] `llvm-as`
Out of these, `touch` is dropped in !9237, and I think `distro-mingw` can also be dropped or renamed to not mention `settings`.
The other would be good additions as fields to `GHC.Toolchain.Target.Target`
---
NB: During development in !9263 we came across multiple tasks and bugs regarding the configuration script. In preparation of merging it, we're opening tickets for the leftover tasks both regarding the new `ghc-toolchain` and the toolchain logic in `configure`. This is one of those tickets.
issue