[Clang][NFCI] Make unchanged global state const (#183478)
To avoid modifications to global state that does not currently need to
be modified, this patch makes a selection of trivial cases const. This
aims to help preserve the intention of these variables and reduce the
potential mutable global state surface of clang.
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Signed-off-by: Steffen Holst Larsen <sholstla@amd.com>
