tests: use RIOTTOOLS variable

Add newly added tests

tests/cb_mux/tests/01-run.py

@@ -39,6 +39,6 @@ def testfunc(child):
 
 
 if __name__ == "__main__":
-    sys.path.append(os.path.join(os.environ['RIOTBASE'], 'dist/tools/testrunner'))
+    sys.path.append(os.path.join(os.environ['RIOTTOOLS'], 'testrunner'))
     from testrunner import run
     sys.exit(run(testfunc))

tests/cb_mux_bench/tests/01-run.py

@@ -20,6 +20,6 @@ def testfunc(child):
 
 
 if __name__ == "__main__":
-    sys.path.append(os.path.join(os.environ['RIOTBASE'], 'dist/tools/testrunner'))
+    sys.path.append(os.path.join(os.environ['RIOTTOOLS'], 'testrunner'))
     from testrunner import run
     sys.exit(run(testfunc))

tests/pkg_tinycbor/tests/01-run.py

@@ -16,7 +16,6 @@ def testfunc(child):
 
 
 if __name__ == "__main__":
-    sys.path.append(os.path.join(os.environ['RIOTBASE'],
-                                 'dist/tools/testrunner'))
+    sys.path.append(os.path.join(os.environ['RIOTTOOLS'], 'testrunner'))
     from testrunner import run
     sys.exit(run(testfunc))

tests/thread_race/tests/01-run.py

@@ -21,6 +21,6 @@ def testfunc(child):
 
 
 if __name__ == "__main__":
-    sys.path.append(os.path.join(os.environ['RIOTBASE'], 'dist/tools/testrunner'))
+    sys.path.append(os.path.join(os.environ['RIOTTOOLS'], 'testrunner'))
     from testrunner import run
     sys.exit(run(testfunc))