Support invocation expressions in LSP Call Hierarchy; bugfixes

[sdedic]

Call hierarchy implementation for LSP throws an exception:

java.lang.NullPointerException
	at org.netbeans.modules.refactoring.java.callhierarchy.CallHierarchyTasks$CallersTask.runTask(CallHierarchyTasks.java:313)
[catch] at org.netbeans.modules.refactoring.java.callhierarchy.CallHierarchyTasks$CallTaskBase.run(CallHierarchyTasks.java:288)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1418)
	at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:45)
	at org.openide.util.lookup.Lookups.executeWith(Lookups.java:278)
	at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2033)

on a trivial source:

package org.yourcompany.yourproject;

public class Locations {

    private void m1() {
        m2();
    }

    private void m2() {
        m3();
    }

    private void m3() {
        throw new UnsupportedOperationException("Not supported yet.");
    }

}

when the caret is positioned at stuff outside of method scope. It does not show any results on method invocations.

---

My bad, the implementation was oversimplified as the code only searched for the enclosing method. This PR extends that to method invocation and new expressions. Some other bugs were also fixed.

[ppisl]

Thanks for fixing this. Looks good to me.