Changed `URL.port` implementation to match [WHATWG
specifications](https://url.spec.whatwg.org/#port-state).
This PR matches the behaviour of other browsers:
1. a `TypeError` must be thrown when passing an URL with an invalid
port to the constructor.
2. When setting an invalid port, using property setter, I haven't found
what should happen in this case, so I mimic **Firefox** & **Node**
behaviour. If an invalid port is set, it will use the previous value.
**Chrome** sets the value to `'0'` if an invalid port is set. I prefer
to keep the previous valid value. (I can use Chrome's behaviour if you
think it's better, it's a simple value change)
```
url.port = '3000'; // valid
url.port = 'deno'; // invalid
assertEquals(url.port, '3000');
```
3. If the port value equals the current protocol default port value,
`port` will be an empty string.
* Reduce "testing" interfaces
* Use a callback instead of a generator for Deno.runTests()
* Default RunTestsOptions::reportToConsole to true
* Compose TestMessage into a single interface
All Deno runtime test files were moved to cli/js/tests/ directory.
It makes a clear distinction that cli/js/tests/ contains code
that is run under Deno runtime as opposed to code in cli/js/ which
is used to create bundle and snapshot with "deno_typescript".
