emacs/bcode: Optimized opcodes

[quasilyte]

For operations like aref it can be a worthwhile to have dedicated opcodes.

;; instead of:
[eval array]
constant 0
aref
;; generate this:
[eval array]
aref-0

This kind of substitution should happen during Emacs Lisp bytecode load.
When loader sees recognizable sequence, it replaces instruction sequence with optimized version.

The performance impact and the amount of code affected should be investigated.