ZJIT: Merge Send and SendWithoutBlock

[tekknolagi]

We have a lot of duplicated code paths now that we optimize both sends with blocks and sends without blocks. Let's merge the HIR instructions SendWithBlock and Send. A PR will need to:

• Merge both instructions into Send
• Make sure all the SendWithoutBlock specializations appropriately check both VM_CALL_ARGS_BLOCKARG and blockiseq
• Have the codegen call rb_vm_opt_send_without_block if we definitely don't have a block (see above) and rb_vm_send otherwise

This should de-dup type_specialize and optimize_c_calls.

[chancancode]

Happy to pick this up as a continuation of ruby#15911. Pretty confident this would work out nicely in type_specialize, will have to see what the rest of the fallout looks like when I try it