This change adds labels to the various global handles used by the wasm
compilation. Labels show up in retaining path information when
debugging lifetime issues.

Change-Id: I9aee20647868b5b758412d231c817909e4130d8c
Reviewed-on: https://chromium-review.googlesource.com/c/1372124Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Stephan Herhut <herhut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58229}