JDK-8009824 has broken webrev with some ksh versions

When executing:

% ksh ../make/scripts/webrev.ksh -b -c JDK-6425477 -m -N

Before JDK-8009824, this worked as expected.

After, it fails with the following error.

ksh ../make/scripts/webrev.ksh -b -c JDK-6425477 -m -N
   SCM detected: mercurial

 No outgoing, perhaps you haven't commited.
      Workspace: /export/home/brwetmor/jdk8/jdk
      Output to: /export/home/brwetmor/jdk8/jdk/webrev
   Output Files:
../make/scripts/webrev.ksh[2588]: syntax error at line 2786 : `NO_OUTGOING' unexpected

I was not able to figure out what " if [[ -v NO_OUTGOING ]]; " actually does. Is this supposed to be a $NO_OUTGOING. And if so, what does -v do? I couldn't find -v documented in either ksh or test.

Joe Darcy was able to get it to run on his Linux machine, but can't on Solaris.