perf(test): remove redundant integration test executions

Remove LLVM backend parametrization from test_exec_smir (keep Haskell
only) and remove test_prove_termination entirely. This eliminates ~54
redundant test executions:

- exec_smir previously ran every test twice (LLVM + Haskell). Since
  Haskell is the backend used for proving, keeping it catches the more
  impactful bugs.
- prove_termination tested the same 19 programs already covered by
  exec_smir[haskell], using the same Haskell backend.

Expected CI time reduction: ~2h37m → ~1h20m.

Resolves #971 (Phase 1)

Author: Stevengre

kmir/src/tests/integration/test_integration.py

@@ -377,40 +377,24 @@ def test_crate_examples(main_crate: Path, kmir: KMIR, update_expected_output: bo
 ]
 
 
-@pytest.mark.parametrize('symbolic', [False, True], ids=['llvm', 'haskell'])
 @pytest.mark.parametrize(
     'test_case',
     EXEC_DATA,
     ids=[name for (name, _, _, _) in EXEC_DATA],
 )
 def test_exec_smir(
     test_case: tuple[str, Path, Path, int],
-    symbolic: bool,
     update_expected_output: bool,
     tmp_path: Path,
 ) -> None:
     _, input_json, output_kast, depth = test_case
     smir_info = SMIRInfo.from_file(input_json)
-    kmir_backend = KMIR.from_kompiled_kore(smir_info, target_dir=tmp_path, symbolic=symbolic)
+    kmir_backend = KMIR.from_kompiled_kore(smir_info, target_dir=tmp_path, symbolic=True)
     result = kmir_backend.run_smir(smir_info, depth=depth)
     result_pretty = kmir_backend.kore_to_pretty(result).rstrip()
     assert_or_update_show_output(result_pretty, output_kast, update=update_expected_output)
 
 
-@pytest.mark.parametrize(
-    'test_data',
-    [(name, smir_json) for (name, smir_json, _, depth) in EXEC_DATA if depth is None],
-    ids=[name for (name, _, _, depth) in EXEC_DATA if depth is None],
-)
-def test_prove_termination(test_data: tuple[str, Path], tmp_path: Path, kmir: KMIR) -> None:
-    testname, smir_json = test_data
-
-    prove_rs_opts = ProveRSOpts(rs_file=smir_json, smir=True)
-
-    proof = KMIR.prove_rs(prove_rs_opts)
-    assert proof.passed
-
-
 SCHEMA_PARSE_DATA = (Path(__file__).parent / 'data' / 'schema-parse').resolve(strict=True)
 SCHEMA_PARSE_INPUT_DIRS = [
     SCHEMA_PARSE_DATA / 'local',