fix: expmod precompile if modulus is 1

[ivokub]

Description

Even though EVM yellow paper defines 0^0=1, then this holds only if modulus is not 0 or 1. In either such case any exponentiation is 0.

Fixes LA audit Issue G

Type of change

• Bug fix (non-breaking change which fixes an issue)

How has this been tested?

• TestEdgeCases - changed the edge case test

How has this been benchmarked?

Not benchmarked

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules