Pull common functions/consts into test_v_helpers.h

Remove the vector zeroing function definition from test files.
This function is defined in `test_v_helpers.cpp`

Pull common constants into `test_v_helpers.h`

Pull templated functions into `test_v_helpers.h`

Update files to adjust names and utilize these shared definitions.

Change-Id: I7aabadb50ed58e5cc6c8e6c5a5a62ba1daed49b1