Semicolons in test names cause 400 errors after the fix for SECURITY-1774 / CVE-2020-2160

Users receive "HTTP ERROR 400 Semicolons are not allowed in the request URI" when clicking on the test name if it contains a semicolon. This appears to be due to the change for [SECURITY-1774](https://www.jenkins.io/security/advisory/2020-03-25/). It is possible to bypass this check by setting ``allowSemicolonsInPath`` to ``true``, but probably not advised in the long run. Maybe this plugin should treat the semicolon (;) as a bad character when building up URLs here:
https://github.com/jenkinsci/junit-plugin/blob/d7d76b48c16b1fdf1354f0c146d8c799d0577164/src/main/java/hudson/tasks/test/TestObject.java#L423

Read src/main/java/hudson/tasks/test/TestObject.java around line 423 and review how test names are used to build URLs after the SECURITY-1774 change. Reproduce the 400 response with a test name containing a semicolon, then verify that clicking such a test name no longer produces the invalid-request error.

Written by the indexing model from the issue text.