Provide assertion facilities on both release and debug mode

[fuzhe1989]

Enhancement

For some logic errors just throw is not safe: the process state might be already wrong. assert can be only used on debug mode. We might need a new way to assert some conditions on both release and debug mode.

It's output could be redirected to fatal.log.

[fuzhe1989]

This article introduces an implementation of an assertion macro.

[JaySon-Huang]

What about just output to the stderr when we meet fatal error?

• Now deployed by TiUP/TiDB-Operator, there is already something help us will collecting the output of stderr
• I think "creating a file on disk" for outputting fatal message is not a very reliable way

[JaySon-Huang]

I remeber that when TiDB panic/out-of-memory, it also use stderr for the panic log (I am not sure whether this behavior is limited by the Golang or not)

[fuzhe1989]

@JaySon-Huang stderr is ok if:

1. It won't lose any log record.
2. It uses the same format as other logs.
3. It could be correctly rotated.

Consider different envs (e.g. deployed by ti.sh), I'm not sure if stderr could handle all of those requirements well.

[breezewish]

Looks like RUNTIME_CHECK and RUNTIME_ASSERT is not used. Maybe we should migrate current if (unlikely(...)) { .. } into this pattern?