Feature/bn128 montgomery multiplication

[AllFi]

What does this PR do?
This PR optimizes BN128Multiplication, and BN128Pairing precompiled contracts by implementing Montgomery form arithmetic. It is worth mentioning that this PR makes BN128Addition a little bit slower because of the overhead of the conversion to and from the Montgomery form.

Why are these changes required?
The current implementation of these precompiles is relatively slow. In general, this hinders on-chain zkSNARKs verification and, consequently, makes zk-based apps almost unfeasible (tronprotocol#4311). This PR is aiming to mitigate this issue.

This PR is far worse than tronprotocol#5507 in terms of optimization but it doesn't require JNI and doesn't introduce a lot of changes in the implementation.

This PR has been tested by:

• Unit Tests
• Manual Testing

Follow up

Extra details
I've performed some benchmarks before and after these modifications. The results are below:

The average time of operations before (Intel(R) Core(TM) i7-10750H CPU, 32 GB RAM):

BN128Addition cost: 41165 ns
BN128Multiplication cost: 3490156 ns
BN128Pairing cost (2 pairs): 87665281 ns

The average time of operations after:

BN128Addition cost: 48147 ns (+17%)
BN128Multiplication cost: 2393792 ns (-31%)
BN128Pairing cost (2 pairs): 57961905 ns (-33%)