Fix vertex fit for dimuon vertices.

allen_rates_effs_dimuon_fix.txtBs2PhiPhi_kalman_hough_dimuon_fix.pdfThis MR removes the PV reconstruction dependence of dimuon vertex reconstruction. This changes the vertex fit so that dimuons are fit regardless of their matched origin PV. This also fixes a problem in the vertex fitter that skipped fitting pairs of tracks with large IP chi2 values. In addition, the 5 lines in the Allen publication have been retuned to achieve 1MHz output. After this MR, the high mass dimuon line performance will be completely independent of PV reconstruction, and the 2-track line will be completely independent of muon ID.

This is marked WIP pending performance tests.