feature: add progress info for loop in main component

[lispc]

after adding these lines, circom can output some progress info when compiling the main component, which is quite helpful for compling huge circuits.

main loop: loopIdx 0 condition i<nTxs at /home/ubuntu/fluidex/circuits/src/block.circom:45
main loop: loopIdx 1 condition i<nTxs at /home/ubuntu/fluidex/circuits/src/block.circom:45
Constraints: 10000
Constraints: 20000
Constraints: 30000
Constraints: 40000
Constraints: 50000
Constraints: 60000
Constraints: 70000
Constraints: 80000
Constraints: 90000
main loop: loopIdx 0 condition i<nTxs at /home/ubuntu/fluidex/circuits/src/block.circom:61
main loop: loopIdx 1 condition i<nTxs at /home/ubuntu/fluidex/circuits/src/block.circom:61
main loop: loopIdx 0 condition i<nTxs at /home/ubuntu/fluidex/circuits/src/block.circom:94
Constraints: 100000
Constraints: 110000
Constraints: 120000
Constraints: 130000
Constraints: 140000
Constraints: 150000
Constraints: 160000