Revert "unit test reworked"

This reverts commit b28da73.

Author: Kontra2B

unit-tests/py/rspy/repo.py

@@ -66,8 +66,8 @@ def find_built_exe( source, name ):
     """
     if platform.system() != 'Linux':
         name += '.exe'
-    paths = os.environ.get('PATH')
-    for p in paths.split(os.pathsep):
+    import sys
+    for p in sys.path:
         exe = os.path.join( p, name )
         if os.path.isfile( exe ):
             return exe

unit-tests/run-unit-tests.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!python3
 
 # License: Apache 2.0. See LICENSE file in root directory.
 # Copyright(c) 2021 RealSense, Inc. All Rights Reserved.