Implement most binary i32 ops in amd64 native backend.

[twitchyliquid64]

> go test -bench=BenchmarkU64Arithmetic github.com/go-interpreter/wagon/exec
goos: linux
goarch: amd64
pkg: github.com/go-interpreter/wagon/exec
BenchmarkU64Arithmetic10Interpreted-8   	  200000	     10012 ns/op
BenchmarkU64Arithmetic10Native-8        	 1000000	      2205 ns/op
BenchmarkU64Arithmetic50Interpreted-8   	   30000	     46081 ns/op
BenchmarkU64Arithmetic50Native-8        	  200000	      9988 ns/op
PASS
ok  	github.com/go-interpreter/wagon/exec	9.382s

[codecov-io]

Codecov Report

Merging #123 into master will decrease coverage by 0.03%.
The diff coverage is 60%.

@@            Coverage Diff             @@
##           master     #123      +/-   ##
==========================================
- Coverage   66.04%   66.01%   -0.04%     
==========================================
  Files          41       41              
  Lines        4138     4172      +34     
==========================================
+ Hits         2733     2754      +21     
- Misses       1134     1147      +13     
  Partials      271      271

Impacted Files	Coverage Δ
exec/internal/compile/scanner.go	0% <0%> (ø)	⬆️
exec/internal/compile/backend_amd64.go	76.74% <62.79%> (-1.17%)	⬇️

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