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

[Justin Riddell via cfe-commits]

Arghnews 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

I'd just pushed a similar (but less neat) version of this, have just tried pasting this version and it works too as a drop in, will use this in the other PR, thank you

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