perf: reduce mem cost on modexp

[driftluo]

What this PR does / why we need it:

This PR reduces mem cost on modexp. Compute gas cost using independent resolution scheme

Which issue(s) this PR fixes:

Fixes #

Which docs this PR relation:

Ref #

Which toolchain this PR adaption:

No Breaking Change

Special notes for your reviewer:

NIL

CI Description

CI Name	Description
Chaos CI	Test the liveness and robustness of Axon under terrible network condition
Cargo Clippy	Run cargo clippy --all --all-targets --all-features
Coverage Test	Get the unit test coverage report
E2E Test	Run end-to-end test to check interfaces
Code Format	Run cargo +nightly fmt --all -- --check and cargo sort -gwc
Web3 Compatible Test	Test the Web3 compatibility of Axon
v3 Core Test	Run the compatibility tests provided by Uniswap V3
OCT 1-5 | 6-10 | 11 | 12-15 | 16-19	Run the compatibility tests provided by OpenZeppelin

CI Usage

Check the CI you want to run below, and then comment /run-ci.

CI Switch

• Chaos CI
• Cargo Clippy
• Coverage Test
• E2E Tests
• Code Format
• Unit Tests
• Web3 Compatible Tests
• OCT 1-5 And 12-15
• OCT 6-10
• OCT 11
• OCT 16-19
• v3 Core Tests

[KaoImin]

/run-ci

[axon-bot]

CI tests run on commit:

• commit id: a7b9835

CI test list:

• Code Format
• Cargo Clippy

Please check ci test results later.