Application fails to start when user's home folder contain certain characters

We recently received a report where an application launched via a JNLP file would failed to start for one user while it worked fine for others when using Icedtea-web 1.8 with OpenJDK 8 on Windows, while it was working for everyone when they used Oracle WebStart.
After investigation, the issue turned out to be that user for whom the application wouldn't start had an apostrophe in their home folder (e.g. `C:\Users\Foo_O'Bar`), which is a legal path on Windows, but that ITW code for crafting new paths for downloaded asset would incorrectly sanitize as `C:\Users\Foo_O_Bar`.
The application would then fail as it attempted to access content in `C:\Users\Foo_O_Bar\...` instead of `C:\Users\Foo_O'Bar\...`

I would like to propose a fix and I have opened PRs for both the `1.8` and `master` branches.