[11u] RFR: 248385: [testbug][11u] Adapt TestInitiExceptions to jtreg 5.1

[Lindenmaier, Goetz]

Hi,

we changed our CI to use jtreg 5.1. Now we see TestInitExceptions
failing on windows because the path is reported differently.

A fix exists in head 
https://bugs.openjdk.java.net/browse/JDK-8246387
but it contains much more changes than are 
not needed for 11.

So I just want to downport this fix in a change of its own:
http://cr.openjdk.java.net/~goetz/wr20/8248385-fix_TestInitException-jdk11/01/
https://bugs.openjdk.java.net/browse/JDK-8248385

Please review.

Best regards,
  Goetz.