Preventing an NPE for compact source files inside test roots.

[lahodaj]

When there is a compact source file inside a test root, there's an NPE:

java.lang.NullPointerException: Cannot load from int array because the return value of "org.netbeans.api.java.source.TreeUtilities.findNameSpan(com.sun.source.tree.ClassTree)" is null
	at org.netbeans.modules.junit.ui.actions.TestClassInfoTask.collect(TestClassInfoTask.java:126)
	at org.netbeans.modules.junit.ui.actions.TestClassInfoTask.doComputeTestMethods(TestClassInfoTask.java:104)
	at org.netbeans.modules.junit.ui.actions.TestClassInfoTask.computeTestMethods(TestClassInfoTask.java:91)
...

The reason is that the synthetic wrapper class does not have a name span (i.e. has null).

The proposal herein is to simply avoid the problems with a null check, and using the class' starting position instead of the name position.

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[donphelix]

LGTM!

[matthiasblaesing]

@lahodaj and this is another merge candidate. I think it makes sense to finish these by merging them.