[BCP-004-01/BCP-006-01] Warn about unlikely constraint_sets

[garethsb]

Generally we expect each entry in the constraint_sets to use the same Parameter Constraints, or at least, not to all use a single different Parameter Constraint.

So this is unlikely to be correct:

"constraint_sets": [
  {
    "param1": { ... }
  },
  {
    "param2": { ... }
  },
  {
    "param3": { ... }
  }
]

Probably this was intended:

"constraint_sets": [
  {
    "param1": { ... },
    "param2": { ... },
    "param3": { ... }
  }
]

Can we capture that as a test case somehow?