RFR: JDK-8204588: Test failures after "Launch Single-File Source-Code Programs"

[Jonathan Gibbons]

Please review two test fixes related to the source launcher feature.

In one test, the fix is to use File.separator to construct "golden 
output" for comparison.

In the other test, the failure was caused by excessively long paths to 
the Java launcher in some test execution environments, causing the 
shebang line to overflow the underlying system limit of 128 characters.  
The fix is to skip test cases when that occurs, as well as to augment 
the test with more tracing information to help diagnose failures on 
remote build and test systems.

The tests are removed from the corresponding ProblemList files.

JBS: https://bugs.openjdk.java.net/browse/JDK-8204588
Webrev: http://cr.openjdk.java.net/~jjg/8204588/webrev.00/index.html

-- Jon