Forgot to revert Hello2_test.go (oops) + enhancements

[texadactyl]

modified:   wholeClassTests/Hello2_test.go

TestRunHello2 was temporarily modified to cause a failure (my bad to leave it as such!). Reverted to former state.

New unit test function: TestRunHello2CauseFail
Redefined: _JVM_ARGS = "-trace:inst"

Now,

• We have both negative and positive tests.
• Demonstrate that tracing causes no false negative results.

While we are at it, let's address JACOBIN-893 by reporting a much more productive fact (class DateFormat is not yet supported):

• modified: gfunction/gfunction.go
• modified: gfunction/javaText/javaTextSimpleDateFormat.go