This commit bans from the model array types in as argument or return
types in CABIFunctionDefinition.
CABIFunctionDefinition implies we're decompiling towards C, and C does
not support array arguments (passed by copy) nor array return types.
Banning these from the model reduces the number of situations where we
have to emit artificial array wrappers (not present in the model) around
types when printing C code, simplifying the handling of such situations
when translating to clift and in general in the decompilation pipeline.
This reworks NameBuilder to ease the transition to the system where
the model will be guaranteed to never contain any name collisions, both
between user-specified names and the automatic ones.