perf: Reduce the amount of alt code generated

[epage]

This takes json/alt/canada from 17ms to 22ms.

Part of #809

[coveralls]

Pull Request Test Coverage Report for Build 16996881311

Details

• 15 of 18 (83.33%) changed or added relevant lines in 1 file are covered.
• 5 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.6%) to 47.131%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/combinator/branch.rs	15	18	83.33%

Files with Coverage Reduction	New Missed Lines	%
src/binary/bits/mod.rs	1	81.71%
src/stream/mod.rs	1	46.23%
src/stream/token.rs	3	37.8%

Totals
Change from base Build 16596311607:	0.6%
Covered Lines:	1618
Relevant Lines:	3433

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💛 - Coveralls