JS: ignore mocked callees for js/superfluous-trailing-arguments

[ghost]

This change whitelists calls with arguments to parameterless functions that trivially throw an exception for the js/superfluous-trailing-arguments query. Such functions are considered placeholders for something else.

Example:

const placeholder = () => {
  throw new Error("Remove this statement and implement this function");
};
placeholder(42, 39); // should not be flagged

The standard evaluations is uneventful. But a run on 200 LGTM projects shows that this change eliminates all of these alerts: https://lgtm.com/query/17012648499980566/?pageIndex=0.

(This change is inspired by the anomaly analysis, I did not open the PR before going on holiday)

[xiemaisi]

I assume you have seen cases where the placeholder function doesn't just have a single throw statement as its body? (That would seem to be a simpler criterion which I would have tried.)

[ghost]

Good question. The motivating anomalies are long gone from memory. But the tests are happy with the simpler not f.getBodyStmt(0) instanceof ThrowStmt (which deliberately does not check the statement count) - should we go with that instead?

[xiemaisi]

Yeah, let's do that instead.

[ghost]

Force-pushed the change.