V8 fails a recently added spec test that when an imported global get
re-exported, it should preserve its identity. This CL fixes the behavior
in V8.

Drive-by change: fix the object printer of globals: a global which
stores a reference type only has a tagged buffer, a global which stores
a value type only has an untagged buffer.

R=clemensb@chromium.org

Bug: v8:10556
Change-Id: I949d147fe4395610cfec6cf60082e1faecb23036
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2235702
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68513}