Correct chrome.exe file resolution on Windows, try different fallbacks.

Currently the task assumes Chrome is located under process.env.LOCALAPPDATA
directory. This may not be as Chrome can be installed globally, to
process.env["PROGRAMFILES(X86)"]. Should Chrome be released for Windows in a 64-bit
flavor, it can be located under process.env.PROGRAMFILES. This commit adds fallbacks
to those paths, being forward-compatible in case 64-bit Chrome gets released for Windows.

Analogous PR for Firefox: https://github.com/karma-runner/karma-firefox-launcher/pull/9