[clang] [llvm] [LLVM][IR] Replace ConstantInt's specialisation of getType() with getIntegerType(). (PR #75217)

[Paul Walker via cfe-commits]

paulwalker-arm wrote:

Most all the recommend changes assume the code paths will work equally well for vector types as they do for scalar types.  Can we be so sure this is the case? This is why I opted to keep the casting assertions with the exception of a few places where I could be sure the code path was clean.

https://github.com/llvm/llvm-project/pull/75217