Add slt test for pushing volatile predicates down

[alamb]

Which issue does this PR close?

• Targets disallow pushdown of volatile functions apache/datafusion#16861

Merging this PR will update apache#16861

Rationale for this change

I think we should have a slt "end to end" reproducer for (not) pushing down volatile predicates

What changes are included in this PR?

Add a slt test

Are these changes tested?

Only tests

Are there any user-facing changes?

[alamb]

This test fails on main like this

Completed 1 test files in 0 seconds                                                                                                                                                                                                  External error: 1 errors in file /Users/andrewlamb/Software/datafusion/datafusion/sqllogictest/test_files/parquet_filter_pushdown.slt

1. query result mismatch:
[SQL] EXPLAIN select a from t_pushdown where b > random();
[Diff] (-expected|+actual)
    logical_plan
    01)Projection: t_pushdown.a
    02)--Filter: CAST(t_pushdown.b AS Float64) > random()
    03)----TableScan: t_pushdown projection=[a, b]
-   physical_plan
-   01)CoalesceBatchesExec: target_batch_size=8192
-   02)--FilterExec: CAST(b@1 AS Float64) > random(), projection=[a@0]
-   03)----DataSourceExec: file_groups={2 groups: [[WORKSPACE_ROOT/datafusion/sqllogictest/test_files/scratch/parquet_filter_pushdown/parquet_table/1.parquet], [WORKSPACE_ROOT/datafusion/sqllogictest/test_files/scratch/parquet_filter_pushdown/parquet_table/2.parquet]]}, projection=[a, b], file_type=parquet
+   physical_plan DataSourceExec: file_groups={2 groups: [[WORKSPACE_ROOT/datafusion/sqllogictest/test_files/scratch/parquet_filter_pushdown/parquet_table/1.parquet], [WORKSPACE_ROOT/datafusion/sqllogictest/test_files/scratch/parquet_filter_pushdown/parquet_table/2.parquet]]}, projection=[a], file_type=parquet, predicate=CAST(b@1 AS Float64) > random(), pruning_predicate=b_null_count@1 != row_count@2 AND CAST(b_max@0 AS Float64) > random(), required_guarantees=[]
at /Users/andrewlamb/Software/datafusion/datafusion/sqllogictest/test_files/parquet_filter_pushdown.slt:411



Error: Execution("1 failures")
error: test failed, to rerun pass `-p datafusion-sqllogictest --test sqllogictests`

Caused by:
  process didn't exit successfully: `/Users/andrewlamb/Software/datafusion/target/ci/deps/sqllogictests-28a2a2385ac148cc parquet_filter_pushdown` (exit status: 1)

[adriangb]

Another place where it would be nice to cast expressions instead of data 😀

[alamb]

All we need is a library that can rewrite expressions ... 😆

[adriangb]

apache#16957