[flags] Enable --compact-map-space with --future

Now that all known correctness issues with map space compaction are
fixed, add more test coverage by enabling it with --future.

Bug: v8:12578
Change-Id: I23d04a162f742480c4e83de1f3980509543e5a97
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3460409Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79100}

src/flags/flag-definitions.h

@@ -519,6 +519,7 @@ DEFINE_WEAK_IMPLICATION(future, short_builtin_calls)
 #if !MUST_WRITE_PROTECT_CODE_MEMORY
 DEFINE_WEAK_VALUE_IMPLICATION(future, write_protect_code_memory, false)
 #endif
+DEFINE_WEAK_IMPLICATION(future, compact_map_space)
 
 DEFINE_BOOL_READONLY(dict_property_const_tracking,
                      V8_DICT_PROPERTY_CONST_TRACKING_BOOL,