copy: Wasm text instruction

;; Copy data in default memory from [100, 125] to [50, 75]
i32.const 50 ;; Destination address to copy to
i32.const 100 ;; Source address to copy from
i32.const 25 ;; Number of bytes to copy
memory.copy  ;; Copy memory

;; Copy in default memory using an S-expression
(memory.copy (i32.const 50) (i32.const 100) (i32.const 25))

;; Copy data within specific memory from [100, 125] to [50, 75]
i32.const 50 ;; Destination address to copy to
i32.const 100 ;; Source address to copy from
i32.const 25 ;; Number of bytes to copy
memory.copy (memory 2) (memory 2) ;; Copy memory within memory with index 2

;; Copy between memories referenced by their names
i32.const 50 ;; Destination address (in $destMem)
i32.const 100 ;; Source address (in $sourceMem)
i32.const 25 ;; Number of bytes to copy
memory.copy (memory $destMem) (memory $sourceMem) ;; Copy memory from "$sourceMem" to "$destMem"

;; Copy between memories using an S-expression
(memory.copy (memory $destMem) (memory $sourceMem) (i32.const 50) (i32.const 100) (i32.const 25))