autopkgtest failures due to missing node-unicode-10.0.0

autopkgtest failures due to missing node-unicode-10.0.0

Since node-unicode-10.0.0 has been replaced by 11.0.0,
it's no longer available (at least on Debian Buster
and Ubuntu Cosmic) and thus the debian/tests' files
should be updated to fix these autopkgtests errors:

1) dependency not installable

 Broken autopkgtest-satdep:amd64 Depends on node-unicode-10.0.0:amd64 < none @un H >
   Removing autopkgtest-satdep:amd64 because I can't find node-unicode-10.0.0:amd64
 Done
 ...
 autopkgtest [21:17:45]: ERROR: erroneous package: Test dependencies are unsatisfiable. A common reason is that your testbed is out of date with respect to the archive, and you need to use a current testbed or run apt-get update or use -U.

2) 'require' test module version

 autopkgtest [17:26:23]: test require: - - - - - - - - - - results - - - - - - - - - -
 require FAIL non-zero exit status 1
 autopkgtest [17:26:24]: test require: - - - - - - - - - - stderr - - - - - - - - - -
 module.js:549
     throw err;
     ^

 Error: Cannot find module 'unicode-10.0.0'
     at Function.Module._resolveFilename (module.js:547:15)
     at Function.Module._load (module.js:474:25)
     at Module.require (module.js:596:17)
     at require (internal/module.js:11:18)
     at [eval]:1:1
     at ContextifyScript.Script.runInThisContext (vm.js:50:33)
     at Object.runInThisContext (vm.js:139:38)
     at Object.<anonymous> ([eval]-wrapper:6:22)
     at Module._compile (module.js:652:30)
     at evalScript (bootstrap_node.js:466:27)

With this patch:

 ...
 Setting up node-unicode-11.0.0 (0~20180730+gitca26ee35-1+version11) ...
 ...
 autopkgtest [17:40:00]: test require: [-----------------------
 autopkgtest [17:40:01]: test require: -----------------------]
 autopkgtest [17:40:01]: test require: - - - - - - - - - - results - - - - - - - - - -
 require PASS
 autopkgtest [17:40:02]: @@@@@@@@@@@@@@@@@@@@ summary
 require PASS