Tests: fix some tests passing even if there are Python errors

Blender was not configured to exit with non-zero return code on Python errors.
A bunch of tests worked around this but not all. This removes the need for such
workarounds.

tests/python/bl_test.py

@@ -136,12 +136,7 @@ def main():
     print("  Running: '%s'" % run)
     print("  MD5: '%s'!" % md5)
 
-    try:
-        result = eval(run)
-    except:
-        import traceback
-        traceback.print_exc()
-        sys.exit(1)
+    result = eval(run)
 
     if write_blend is not None:
         print("  Writing Blend: %s" % write_blend)
@@ -188,10 +183,4 @@ def main():
 
 
 if __name__ == "__main__":
-    # So a python error exits(1)
-    try:
-        main()
-    except:
-        import traceback
-        traceback.print_exc()
-        sys.exit(1)
+    main()