Fix #7793: Handle context parameters in resolveOverloaded

[odersky]

resolveOverloaded now takes into account whether arguments are using
clauses or regular arguments.

[odersky]

There are essentially two ways to solve #7793. We could fiddle with isApplicable to take account of arguments using clauses. #8395 did this by trying both scenarios: one wether the arguments are assumed to be passed regularly, the other where they are passed in a using clause. To avoid exponential blow-up one could refine this by passing the kind of argument clause as an additional parameter to isApplicable.

On the other hand, this is only needed for overloading resolution. In other scenarios, we adapt to the kind of argument clause before computing application types. And fiddling with isApplicable is only one measure of several to make resolveOverloaded work in scenarios like #7793. So it seems better to add the necessary logic directly to resolveOverloaded, which is what this PR does.