Bump org.antlr:antlr4-runtime from 4.9.3 to 4.12.0 #3068

Tests

• ❌ key.core.testgen:test (11 succeeded, 2 failed)
• ❌ key.core:test (137 succeeded, 682 failed, 72 skipped)
• ❌ key.core:testProveRules (0 succeeded, 1 failed)
• ❌ key.core:testRunAllFunProofs (0 succeeded, 47 failed)
• ❌ key.core:testRunAllInfProofs (1 succeeded, 29 failed)
• ✅ key.removegenerics:test (45 succeeded)
• ✅ key.ui:test (5 succeeded)
• ✅ key.util:test (132 succeeded)
• ❌ keyext.exploration:test (0 succeeded, 3 failed)
• ✅ recoder:test (14 succeeded, 15 skipped)