tests: Replace umodule with module everywhere.

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

tests/extmod/json_dumps_float.py

@@ -0,0 +1,8 @@
+try:
+    import json
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+print(json.dumps(1.2))
+print(json.dumps({1.5: "hi"}))