Some of the Float(32|64) to CompressedSigned cases had their functions
defined already so they are virtually free to implement.

We are still missing the unsigned case so I am keeping the TODO.

Cq-Include-Trybots: luci.v8.try:v8_linux64_pointer_compression_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_arm64_pointer_compression_rel_ng
Bug: v8:7703
Change-Id: Ibf40d5948226fd48aebe7f8e257c117d6a5ad478
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1708483Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63143}