test: refresh PostgreSQL compatibility baselines after grammar expansion

Regenerate the PostgreSQL 18.4 report, complete accepted-statement inventory
and selected CI fixtures from the final parser sources. Force a library
rebuild first: the existing Makefile does not track header dependencies, and
an earlier snapshot linked stale parser code. Keep the pinned PostgreSQL
17.7/18.4 oracle revisions and the 51,415-statement target corpus unchanged.

The final inventory contains 19,139 complete-input AST results, 1,274
classification-only results, 28,678 trailing-input results, 2,194 statement
type mismatches, 95 partial results and 35 errors. Relative to the snapshot
before the latest query/API additions, complete-input coverage increases by
2,803 cases. Review the four formerly complete EXPLAIN/window queries that
now expose the unsupported <-> operator instead of omitting expressions.
The additional stale-build transitions do not lose any previously complete
case relative to that pre-feature snapshot.

Correct the runner fixture to expect unconsumed CREATE TABLE definitions and
unknown-command tails rather than claiming all input was consumed. The report
checks classification, status, AST presence and input consumption; it does not
establish node-by-node AST equivalence or production workload coverage. The
large generated diff also incorporates changes since the older committed
baseline and must not be read entirely as gains from this patch.

Validation: a forced full C++ rebuild passes 1,354 active tests with 37
backend-dependent skips and builds the corpus harness. All 87 compatibility
harness tests pass and all 33,534 regenerated CI cases replay successfully.
These are correctness fixtures and coverage reports; timing benchmarks and
benchmark harnesses are intentionally excluded.

Author: renecannao