Proposal: remove numberOfArgs assertion on FunctionModel

[sylvainpolletvillard]

In v3, all FunctionModels come with a built-in assertion that checks if a function is not called with more parameters that it can handle. I propose to remove this assertion in v4, and make it opt-in on specific function models instead.

Arguments:

• this is a quite important perf penalty that applies to all function models, and is difficult / non-intuitive to opt-out
• the service provided by this assertion is not very valuable, since this can be statically analysed, and is actually already reported by common editors and linters
• the assertion sometimes report false positives when the function refer to the arguments variable for example
• this is the only built-in assertion for the whole library, so dropping this edge case helps making the library smaller and more consistent