Cache output `equivalence_properties` in ProjectionExec

[gruuya]

Which issue does this PR close?

Closes #9084.

Rationale for this change

Avoid potential exponential explosions in branching calls to output_partitioning and equivalence_properties in certain plan combinations.

What changes are included in this PR?

Simply store the equivalence_properties, which are always calculated anyway in ProjectionExec.

Are these changes tested?

They were tested on the example from https://github.com/apache/arrow-datafusion/issues/9084

Are there any user-facing changes?

Not really, apart from not stalling TPC-DS q64.