Update try_swap_parallel, nowadays no segment fault

Today, I modified 2 bugs:
1) The most important modification was delete max_pins_per_clb = 0,
and delete this parameter in initial_swap_data() function;

2) I found that in VPR5.0.2, IO_TYPE grid had 24 pins, so I modified
g_pins_on_block[IO_TYPE], g_pins_on_block[INPAD_TYPE] and
g_pins_on_block[OUTPAD_TYPE] as 24.

However, the placement result wasn't same with VPR5.0.2, and there are
many errors in placement results. I assumed that there must some errors
in find_to_block_parallel(), so I new added some assert() macro.