testing: report line number for F.Add call with mismatched type

[jayconrod]

If F.Add is called with values with types that don't match the fuzz function's parameter types, f.Fuzz reports a fatal error and exits.

func Fuzz(f *testing.F) {
  f.Add("string not bytes")
  f.Fuzz(func(t *testing.T, b []byte) { ... })
}

The error message should point to the location where F.Add was called to make the error easy to correct.

A vet check (#46218) should report errors for these calls at build time.

[gopherbot]

Change https://go.dev/cl/395374 mentions this issue: testing: report line number for F.Add call with mismatched type