* codegen: LLVMConstInlineAsm is deprecated.
* codegen: replace commas in asm constraint strings by pipes as required by LLVM.
* ir: enforce usage of '=' constraint modifier for inline assembly outputs.
Others are not currently supported and this was just asserted alter in `ir_render_asm`.
* asm: forbid comptime_int/floats as inputs in favor of explicitely sized constants.
Fixes a crash due to comptime_int/floats having no type_ref.
* asm: handle inputs with integers of <8 or non power of 2 bitsize.
We widen them to the next highest power of two.