[clang] [WIP][Clang][bytecode] interp__builtin_elementwise_int_binop - allow RHS operand to be a scalar (PR #156017)

[Simon Pilgrim via cfe-commits]

RKSimon wrote:

@Arghnews Feel free to copy the relevant interp__builtin_elementwise_int_binop "Vector + Scalar" code from this and use it #155542 - I'm not sure if I'll get the rotate changes finished today

https://github.com/llvm/llvm-project/pull/156017