Reland of [debugging] print ranges for consecutive values with %DebugPrint (patchset #1 id:1 of https://codereview.chromium.org/2181093003/ )

Reason for revert:
Dummy initializing variables to make compilers happy.

Original issue's description:
> Revert of [debugging] print ranges for consecutive values with %DebugPrint (patchset #2 id:20001 of https://codereview.chromium.org/2169143003/ )
>
> Reason for revert:
> breaks android build due to uninitialized variable.
> https://build.chromium.org/p/client.v8.ports/builders/V8%20Arm%20-%20debug%20builder/builds/2034
>
> Original issue's description:
> > [debugging] print ranges for consecutive values with %DebugPrint
> >
> > With this CL repeated values in elements are combined into a single printout with a range.
> >
> > BEFORE:
> > - elements = {
> >   0: <undefined>
> >   1: <undefined>
> >   2: <the_hole>
> > }
> >
> > AFTER:
> >  - elements = {
> >        0-1: <undefined>
> >          2: <the_hole>
> > }
> >
> > BUG=
> >
> > Committed: https://crrev.com/ec4165742088043d8fede38db21a281e16682adb
> > Cr-Commit-Position: refs/heads/master@{#38069}
>
> TBR=yangguo@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=
>
> Committed: https://crrev.com/7b2cd8b988d257f22afc7c03cd2caf8ba2e2b3a3
> Cr-Commit-Position: refs/heads/master@{#38071}

TBR=yangguo@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review-Url: https://codereview.chromium.org/2182203004
Cr-Commit-Position: refs/heads/master@{#38080}