Many instructions are declared using DECLARE_INSTRUCTION (via
ASSEMBLER_INSTRUCTION_LIST), and each of them currently defined eight
templates for different sizes and different number of arguments.
This CL reduces this to three variadic templates per instruction.

R=zhin@chromium.org

Bug: v8:12244
Change-Id: Ibd75c55e757f917eb1e9b54c0a1a79632a1ba6d8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3181103Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77057}