tests: move "venv" to "build-root" directory from "test" directory

Type: refactor

- refactored VPP test code to remove "ignore_path" variable
  from "discover_tests" function and "run_test" code
- configured VPP test makefile, config file, and 'run.sh' shell script
  to move "venv" directory from "test" dir to "build-root" dir

Signed-off-by: Saima Yunus <yunus.saima.234@gmail.com>
Change-Id: Id2beecbb99f24ce13ed118a1869c5adbef247e50

test/run_tests.py

@@ -947,11 +947,10 @@ if __name__ == "__main__":
 
     filter_cb = FilterByTestOption(filter_file, filter_class, filter_func)
 
-    ignore_path = config.venv_dir
     cb = SplitToSuitesCallback(filter_cb)
     for d in config.test_src_dir:
         print("Adding tests from directory tree %s" % d)
-        discover_tests(d, cb, ignore_path)
+        discover_tests(d, cb)
 
     # suites are not hashable, need to use list
     suites = []