Fix Typed Class Constants parsing

[genintho]

Fix #1133

• make sure all variation of class constant are still being supported
• Throw a clear error when the parser detect typed class constants by the PHP version configured does not match

[cseufert]

It looks as though the source code location is lost during parsing as well

[cseufert]

Attribute groups are lost too

[cseufert]

This does not make sense either, nullable should be a bool value? looks like attrGroups and nullable are switched around somewhere

[cseufert]

It looks like the refactor has significantly changed the AST output around attrgroups, as the attrGroups should not be affected, also I would expect nullable to be a boolean type.

[genintho]

@cseufert Yeah there are bugs in the logic.
Can you look at this different PR I made that fix some other bugs I found while working on this #1141

[genintho]

I figured out the core issue: the AST ClassConstant object constants which is an array of AST "Constant" object.

ClassConstant {
          "attrGroups": undefined,
          "constants": [
            Constant {
              "kind": "constant",
              "name": Identifier {
                "kind": "identifier",
                "name": "CON_2",
              },
              "value": String {
                "isDoubleQuote": true,
                "kind": "string",
                "raw": ""Hello world!"",
                "unicode": false,
                "value": "Hello world!",
              },
            },
          ],
          "final": false,
          "kind": "classconstant",
          "nullable": [],
          "type": null,
          "visibility": "",
        },

The code is reading a list of constant, to support this syntax.

class Foo {
    const PRI1 = 'baz', PRI2 = 'baz2';
}

But the implementations made the assumption that all constant have the same type/nullable: type and nullable was added to "ClassConstant", not "Constant".

That's incorect, because this code is valid:

class Foo {
	private const PRI1 = 'baz', string PRI2 = 'baz2', int PRI3 = 5;
}

The last commit I pushed, 94d4069 keep the type on the "ClassConstant" object and create only 1 constant object per ClassConstant. That works, but it is a less accurate representation of the code being parsed.

Now I am going to fix that by moving the type to the AST "Constant" object.

[genintho]

If we do not want those to be part of the AST, we need to completly decouple the ClassConstant object from the Constant object.

[genintho]

@cseufert code is ready for another review

[genintho]

Actually, they are still bug. I will reopen when it is fully ready.