Implement full records support

[nrmancuso]

Per discussion at #8023 (comment) and #8023 (comment). While a superficial implementation of Java 14 records will close Issue #8023, we need to make an issue for full records support, extending our support of records to build the full AST under the RECORD_DEF token.

Topics of discussion:

1. Which checks should be extended to support records
2. How to handle constructors. While a new compact constructor for records must be defined, records must also support canonical constructors with some restrictions (see JLS). Should this compact constructor be added to field grammar?
3. New tokens to introduce. Per Allow unsupported syntax, like record classes #8023 (comment) we will be introducing RECORD_COMPONENT_DEF and RECORD_CTOR_DEF, is this all?
4. ...

http://cr.openjdk.java.net/~gbierman/jep359/jep359-20191031/specs/records-jls.html#jls-8.10.5

Group Chats:
messages1.pdf
messages2.pdf

[pbludov]

The checks to be reviewed:

• All annotation checks, as RECORD_COMPONENT may be annotated
• All type-specific checks, as records are another kind of type
• Some whitespace checks, as {} (empty body) is common for records

[nrmancuso]

The checks to be reviewed..

Thank you, I will make note of any insight for supporting these checks while I work on #8023.

[pbludov]

From #8308

Adding new keywords to a language is very difficult, since they are probably used as identifiers in the existing code. Our parser should accept such keyword as an identifier, but we need a new check. Something like AvoidUsingKeywordsAsIdentifiers.