style: refactor crypto lib to consistent verification style

[0xmountaintop]

in vss::Share::Verify & mta::ProofBob::Verify & all other ValidateBasic()/Validate(), boolean computations are returned directly.

• https://github.com/binance-chain/tss-lib/blob/e860e36eaaa63afcaf1e5a0ed79b6f56362e88c8/crypto/vss/feldman_vss.go#L93
• https://github.com/binance-chain/tss-lib/blob/e860e36eaaa63afcaf1e5a0ed79b6f56362e88c8/crypto/mta/proofs.go#L276
• https://github.com/binance-chain/tss-lib/blob/e860e36eaaa63afcaf1e5a0ed79b6f56362e88c8/crypto/mta/proofs.go#L279
• https://github.com/binance-chain/tss-lib/blob/e860e36eaaa63afcaf1e5a0ed79b6f56362e88c8/crypto/ecpoint.go#L76
• ...

However, this is not the case in commitment and schnorr_proof package.

This PR refactor them to consistent verification style, and may save condition branch executions if being compiled without optimization.