Tweak the register allocation logic in liftoff-compiler.cc. If we reuse
src1 or src2 for dst, it complicates the logic in the codegen
significantly. We will need to check which operand dst is equals to,
back it up, then make sure the mask ends up in dst (since thats how vbsl
and bsl works, the first operand holds the mask and is overwritten). By
tweaking the allocation logic, no code gen is required for the other
backends.

Bug: v8:9909
Change-Id: I17843322508b18247c91e5959cf1b996b7f6a61d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2171468
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67481}