Out-of-range status codes should be coalesced to "UNKNOWN"

[dfawley]

Per grpc/grpc#13321 (comment), we should not set the status code to an out-of-range value; we should force it to UNKNOWN when that happens instead.

[jeanbza]

The linked PRs should cover all codes. There were many instances of the first two codes in the list (NOT_FOUND, INVALID_ARGUMENT) which is why I created separate PRs, but then the rest of the errors had hardly any occurrences heh. Oh well. Let me know if you'd like me to merge them.

[jeanbza]

@menghanl I believe this is finished, now

[menghanl]

@jadekler we still return unexpected code in function convertCode, including OutOfRange.

grpc-go/go17.go

Lines 76 to 85 in 583a630

	func convertCode(err error) codes.Code {
	switch err {
	case nil:
	return codes.OK
	case io.EOF:
	return codes.OutOfRange
	case io.ErrClosedPipe, io.ErrNoProgress, io.ErrShortBuffer, io.ErrShortWrite, io.ErrUnexpectedEOF:
	return codes.FailedPrecondition
	case os.ErrInvalid:
	return codes.InvalidArgument

[jeanbza]

Shoot good point. I'll fix that tn