opt: encoder VM

[AsterDY]

Optimizations

• append chars instead of string
• use std strconv.AppendInt() instead of native I64toa
• force inline call_xx_marshaler()
• asm2arm: use dynamic PC-relative offset JUMP to replace CALL

[codecov-commenter]

Codecov Report

Attention: 44 lines in your changes are missing coverage. Please review.

Comparison is base (820917d) 61.58% compared to head (ed746bd) 61.80%.

Files	Patch %	Lines
internal/encoder/vm/vm.go	2.56%	38 Missing :warning:
internal/encoder/alg/spec.go	0.00%	6 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## test/aarch64 #593 +/- ## ================================================ + Coverage 61.58% 61.80% +0.22% ================================================ Files 84 84 Lines 10363 10345 -18 ================================================ + Hits 6382 6394 +12 + Misses 3597 3568 -29 + Partials 384 383 -1 ```

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