[clang][NFC] Generate the {Type,ArrayType,UnaryExprOrType,Expression}Traits...

...enumerations from TokenKinds.def and use the new macros from TokenKinds.def
to remove the hard-coded lists of traits.

All the information needed to generate these enumerations is already present
in TokenKinds.def. The motivation here is to be able to dump the trait spelling
without hard-coding the list in yet another place.

Note that this change the order of the enumerators in the enumerations (except
that in the TypeTrait enumeration all unary type traits are before all binary
type traits, and all binary type traits are before all n-ary type traits).

Apart from the aforementioned ordering which is relied upon, after this patch
no code in clang or in the various clang tools depend on the specific ordering
of the enumerators.

No functional changes intended.

Differential Revision: https://reviews.llvm.org/D81455

Reviewed By: aaron.ballman