Code stub assembler does implicit compression / decompression when loading values from
the heap. As a result, we shouldn't expose explicit compress / decompress operators.

BUG=v8:7703

Change-Id: I72b7b862b48f19e918db0e283d1be065a2651b44
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1637879
Auto-Submit: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61955}