=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?
in the 7000 case the 31 really means "31 ops/ms", it's the "horrible 7000chars actor name" (the old impl would just blow up).

more data:

(changed scale to micros)
```
7000 chars
[info] a.a.ActorPathValidationBenchmark.handLoop7000           thrpt        10       29.226        1.178   ops/ms
[info] a.a.ActorPathValidationBenchmark.handLoop7000_opt       thrpt        10       33.335        0.934   ops/ms
 --- old7000 blows up

"actor-1"
[info] a.a.ActorPathValidationBenchmark.handLoopActor_1        thrpt        10       37.429        2.782   ops/us
[info] a.a.ActorPathValidationBenchmark.handLoopActor_1_opt    thrpt        10       40.259        1.670   ops/us
[info] a.a.ActorPathValidationBenchmark.oldActor_1             thrpt        10        1.577        0.048   ops/us
```