Simplify and use AbiDecoder function selector helpers

[iamacook]

Summary

We were generating AbiDecoder['helpers'] by decoding function data and returning true/false according to what it decodes. A more efficient method is comparing the beginning of the data against the function selector.

This adjusts the logic of AbiDecoder['helpers'] to instead compare the beginning of the function data against the relevant selector.

Changes

• Optimise AbiDecoder['helpers'] generation
• Remove SetPreSignatureDecoder['isSetPreSignature'] and replace all usage with this.helpers.isSetPreSignature

[coveralls]

Pull Request Test Coverage Report for Build 9463628425

Details

• 5 of 5 (100.0%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.04%) to 92.668%

---

Files with Coverage Reduction	New Missed Lines	%
src/routes/transactions/entities/tests/human-description.builder.ts	1	80.0%

Totals
Change from base Build 9460927247:	-0.04%
Covered Lines:	7154
Relevant Lines:	7419

---

💛 - Coveralls