chainDump: fix and improve print-out formatting
Fixes ATR-21127 (type conversion error) and improves the print-out formatting.
Examples of updated output from HLTChain.txt:
All 1097125 1092126
HLT_2e17_etcut_L12EM15VH 0 0
HLT_2e3_etcut_L12EM3 11 11
HLT_2g20_tight_L12EM20VH 175 177 <<<<<<<<<<
HLT_2g35_etcut_L12EM20VH 8925 8909 <<<<<<<<<<
HLT_2g35_medium_L12EM20VH 106 105
HLT_2j330_a10t_lcw_jes_35smcINF_L1J100 238 233 <<<<<<<<<<
HLT_2mu10_bJpsimumu_L12MU10 23 23
HLT_2mu10_bUpsimumu_L12MU10 0 0
HLT_2mu14_L12MU10 434 436 <<<<<<<<<<
HLT_xe100_mht_L1XE50 10175 - <<<<<<<<<<
HLT_xe100_pfsum_L1XE50 6982 - <<<<<<<<<<