Type Checker: Fix broken directive in MSR test
@@ -181,7 +181,7 @@ obviously cannot be linked together.
```sh
kdb setmeta spec/tests/typechecker/key2 fallback/#1 spec/tests/typechecker/key1
# RET: 5
-# STDERR-REGEX: .*Could not not deduce:*
+# STDERR: .*Could not deduce:.*
sudo kdb umount spec/tests/typechecker
```
