Position information overhaul #3049

Tests

• ❌ key.core.testgen:test (11 succeeded, 2 failed)
• ❌ key.core:test (386 succeeded, 436 failed, 72 skipped)
• ❌ key.core:testProveRules (0 succeeded, 1 failed)
• ❌ key.core:testRunAllFunProofs (1 succeeded, 46 failed)
• ❌ key.core:testRunAllInfProofs (1 succeeded, 29 failed)
• ✅ key.removegenerics:test (45 succeeded)
• ✅ key.ui:test (5 succeeded)
• ✅ key.util:test (134 succeeded)
• ❌ keyext.exploration:test (0 succeeded, 3 failed)
• ❌ keyext.slicing:test (2 succeeded, 10 failed)
• ✅ recoder:test (14 succeeded, 15 skipped)