=act reimplement actor path validation without regex

While working on fixing https://github.com/akka/akka/pull/16347 I decided to let go of the regexp and impl simpler methods.

I found that on a smaller scale the new methods are way better, but in the grand scheme of things there seems to be a larger trade off at higher percentiles.

I got to:

```
+[info] a.a.ActorCreationBenchmark.synchronousStarting       ss     20000       16.413        1.494       us
```

from an initial:

```
+[info] a.a.ActorCreationBenchmark.synchronousStarting       ss     20000       27.022        1.903       us
```

but the higher percentiles got hit quite hard (*averages mean nothing* mantra kicks in...).

Note: These implementations pass tests in akka actor and survive the `...|%67` which caused the regex based impl to blow up.

Do you think it is worth trying one of these impls or am I on the wrong way?
What's the difference in perf between that approach and this:

    final val symbols = "-_.*$+:@&=,!~\';" // Put this in an object so it becomes a constant
    (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || (symbols.indexOf(c) != -1)