restoreCache only cleanup in finally if archivePath is set

[jsoref]

When running tests for actions/download-artifact, I see output akin to:

[Test/Build]   💬  ::debug::Resource Url: http://192.168.1.131:60101/_apis/artifactcache/cache?keys=node-cache-Linux-npm-e6ea06a810d13d06734e17284172c796edb36687728216c316fe3e8dbe04d235&version=b3f0cb83629d634645a5146420c017462ebb5229bd60271a7a86e489a6066469
[Test/Build]   💬  ::debug::Failed to delete archive: Error: ENOENT: no such file or directory, unlink ''

The current code is broken. -- The try block includes a lot of code that runs and can return early before it sets archivePath, and yet the finally unconditionally calls utils.unlinkFile(archivePath).