cleaned up commented code

Author: Mansib Rahman

toolchain/mfc/case_validator.py

@@ -1487,8 +1487,6 @@ def check_chemistry(self):
         is provided. No static validation is performed here - chemistry will fail at
         runtime if misconfigured.
         """
-        # Fetch global chemistry and diffusion flags
-        # chemistry = self.get("chemistry", "F") == "T"
         chemistry = self.flag("chemistry")
         diffusion = self.get("chem_params%diffusion", "F") == "T"
         num_fluids = self.get("num_fluids")