Add tests of loading all the models

Summary:
... and improved the exception message.

Before:

```
Unexpected limit type 'minmax' in parameter configuration : limit neck_ty minmax [-1.00, 0.50]
```

After:

```
Failed to parse parameter configuration 'limit neck_ty minmax [-1.00, 0.50]'. This could be due to an unsupported limit type 'minmax' or failure to find the parameter name 'neck_ty'.
```

Reviewed By: yutingye

Differential Revision: D63047012

fbshipit-source-id: b9d8bc2d576992bd170aabe8a93dcfc8590098d5

momentum/io/skeleton/parameter_limits_io.cpp

@@ -280,7 +280,11 @@ ParameterLimits parseParameterLimits(
           "Deprecated parameter limit type: {} (typo). Please use 'ellipsoid' instead.", type);
       parseEllipsoid(pl, valueStr, skeleton, jointIndex);
     } else {
-      MT_THROW("Unexpected limit type '{}' in parameter configuration : {}", type, line);
+      MT_THROW(
+          "Failed to parse parameter configuration '{}'. This could be due to an unsupported limit type '{}' or failure to find the parameter name '{}'.",
+          line,
+          type,
+          parameterName);
     }
   }
   return pl;