trace_processor: add ahead-of-time index computation on repeated queries

This CL adds intelligent ahead-of-time creation of an index for queries
where the same cursor is used to repeatedly find different partitions of
a column.

This occurs very commonly on joins between tables (e.g. the join of counter
track table with counters table) and without this optimization metric
performance regresses significantly.

Context: go/perfetto-tp-refactor
Bug: 135177627
Change-Id: I9486e013db87f4c5ec16083ec8c7f4fbaaaaa4c7