Dataflow: Minor join-order fix

[aschackmull]

This was identified by the join-order metric. It's not recursive, so it didn't hurt us too much, but it's an easy fix.

Before:

[2025-01-16 10:32:29] Evaluated non-recursive predicate DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::S6Graph::fwdFlowInStep/10#316df909@3f9c0ft4 in 13ms (size: 38324).
Evaluated relational algebra for predicate DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::S6Graph::fwdFlowInStep/10#316df909@3f9c0ft4 with tuple counts:
          15972   ~0%    {7} r1 = JOIN `num#DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::TSummaryCtxNone#7d1df047` WITH `project#DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::FwdFlowInNoThrough::fwdFlowInValidEdgeTypeFlowEnabled/8#ed2cbed3` CARTESIAN PRODUCT OUTPUT Rhs.0, Rhs.1, Rhs.4, Rhs.5, Lhs.0, Rhs.2, Rhs.3
          26378   ~0%    {10}    | JOIN WITH `DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::fwdFlowIntoArg/9#973fa733#reorder_0_2_6_8_1_3_4_5_7` ON FIRST 4 OUTPUT Lhs.0, Lhs.5, Rhs.4, Lhs.1, Lhs.6, Rhs.5, Lhs.4, Rhs.6, Rhs.7, Rhs.8
                     
           4063   ~0%    {6} r2 = SCAN `DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::TSummaryCtxSome#abb16013` OUTPUT In.1, In.2, In.3, In.4, In.0, In.5
        3282287   ~0%    {11}    | JOIN WITH `DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::fwdFlowIntoArg/9#973fa733#reorder_0_2_6_8_1_3_4_5_7_467801523#join_rhs` ON FIRST 4 OUTPUT Rhs.4, Rhs.5, Lhs.4, Rhs.7, Rhs.8, Lhs.0, Lhs.1, Lhs.2, Lhs.3, Lhs.5, Rhs.6
          11946   ~1%    {10}    | JOIN WITH `project#DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::FwdFlowInThrough::fwdFlowInValidEdgeTypeFlowEnabled/8#5803fd18_012453#join_rhs` ON FIRST 5 OUTPUT Lhs.0, Lhs.2, Lhs.5, Lhs.1, Rhs.5, Lhs.10, Lhs.9, Lhs.6, Lhs.7, Lhs.8
                     
          38324   ~0%    {10} r3 = r1 UNION r2
                         return r3

After:

[2025-01-16 10:31:51] Evaluated non-recursive predicate DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::S6Graph::fwdFlowInStep/10#316df909@d5c761bm in 5ms (size: 38324).
Evaluated relational algebra for predicate DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::S6Graph::fwdFlowInStep/10#316df909@d5c761bm with tuple counts:
        15972   ~0%    {7} r1 = JOIN `num#DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::TSummaryCtxNone#7d1df047` WITH `project#DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::FwdFlowInNoThrough::fwdFlowInValidEdgeTypeFlowEnabled/8#ed2cbed3` CARTESIAN PRODUCT OUTPUT Rhs.0, Rhs.1, Rhs.4, Rhs.5, Lhs.0, Rhs.2, Rhs.3
        26378   ~0%    {10}    | JOIN WITH `DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::fwdFlowIntoArg/9#973fa733#reorder_0_2_6_8_1_3_4_5_7` ON FIRST 4 OUTPUT Lhs.0, Lhs.5, Rhs.4, Lhs.1, Lhs.6, Rhs.5, Lhs.4, Rhs.6, Rhs.7, Rhs.8
                   
         6214   ~5%    {6} r2 = SCAN `project#DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::FwdFlowInThrough::fwdFlowInValidEdgeTypeFlowEnabled/8#5803fd18` OUTPUT In.0, In.1, In.4, In.5, In.2, In.3
        11946   ~0%    {9}    | JOIN WITH `DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::fwdFlowIntoArg/9#973fa733#reorder_0_2_6_8_1_3_4_5_7` ON FIRST 4 OUTPUT Lhs.4, Rhs.4, Rhs.6, Rhs.7, Rhs.8, Lhs.0, Lhs.1, Lhs.5, Rhs.5
        11946   ~1%    {10}    | JOIN WITH `DataFlowImpl::MakeImpl<Location::Location,DataFlowImplSpecific::JavaDataFlow>::Impl<SensitiveLoggingQuery::SensitiveLoggerFlow::C>::Stage6::TSummaryCtxSome#abb16013` ON FIRST 5 OUTPUT Lhs.5, Lhs.0, Lhs.1, Lhs.6, Lhs.7, Lhs.8, Rhs.5, Lhs.2, Lhs.3, Lhs.4
                   
        38324   ~0%    {10} r3 = r1 UNION r2
                       return r3

(I've also piggy-backed a commit that deletes an outdated comment)

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