Test testNeuronBuildTree() failure

Created by: subhacom

For last few days, CTest reports that one test is continuously failing:

 /data/dilawars/moose3.0.1/biophysics/testBiophysics.cpp:1587: 

void testNeuronBuildTree(): Assertion `val.size() == 7 * elist.size()' failed.

```~~~

I tested it both Makefile and Cmake build system. I can reproduce it with checkin 6779. 

Reported by: dilawar