Hibernate depends on antlr:antlr:2.7.7 (the latest version on Antlr 2)
and fails with earlier 2.7.x versions due to a missing method. This
can cause problems for Maven users if they also depend on something that
pulls in an earlier version of Antlr, such as
spring-boot-starter-velocity. Gradle users are unaffected as, when
multiple versions of a dependency are found in the graph, Gradle will
choose the latest version.

This commit adds dependency management for antlr:antlr:2.7.7 to ensure
that the latest, and Hibernate compatible, version of Antlr 2 is used.

Closes gh-2814