top_n support for Tc file. This PR will be over several commits for easier sanity checking against the CI.
commit 00658125b12a84237eb2958a2abe41c70d86ffdf - no changes in files
commit 455cc74a309f26d7a4619814647ceb09ead66b74 - saving all columns, changes in all csv files are simply reordering of columns (verified through bcompare).
commit 3a0a9f80764cd215a4989eb492f427a735669a94 - updated defaults to 30 (no change in test behavior).
top_nsupport forTcfile. This PR will be over several commits for easier sanity checking against the CI.bcompare).30(no change in test behavior).