Usage of \p{Alpha} does not work as expected on earlier versions of JDK 17

[Naros]

Per discussion in antlr/grammars-v4#4018, raising the issue here.

The problem is that to recognize several characters, such as those in this SQL fragment:

select a ä, b Ḅ from dual;

When Using JDK 17.0.10, the use of \p{Alpha} was sufficient to match against any latin character, including ä and Ḅ, but when using JDK 17.0.3 this was insufficient as regular characters were no longer being matched.

The solution found for JDK 17.0.3 was to use a combination of A-Z and \p{Alpha} as shown in the aforementioned PR.