Sonic: nested slices references don't work on arm64

[gbjk]

With the addition of sonic as the default json decoder, we've found that okx does not unmarshal responses correctly.
Specifically, okx's SendHTTPRequest accepts any which should contain a pointer to something.
It then tries to wrap that in another slice of any in most situations, depending on the useAsItIs flag and the type of the data.
The issue is that sonic replaces the pointer inside the top slice, and so the caller's pointer is never changed.
The cleanest way to reproduce this I've found so far is:

func TestSonic(t *testing.T) {
	a := []string{}
	b := []any{&a}
	if err := sonic.ConfigStd.Unmarshal([]byte(`[["one","2"]]`), &b); err != nil {
		t.Fatalf("Unmarshal must not error: %s", err)
	}
	if _, ok := b[0].(*[]string); !ok {
		t.Fatalf("b[0] must still a *[]string; Got: %T", b[0])
	}
	if b[0] != &a {
		t.Error("b[0] must still be *a")
	}
}

Giving:

GOARCH=arm64 go test ./exchanges/okx/... -run TestSonic
--- FAIL: TestSonic (0.00s)
    okx_test.go:598: b[0] must still a *[]string; Got: []interface {}

versus:

GOARCH=amd64 go test ./exchanges/okx/... -run TestSonic
--- PASS: TestSonic (0.01s)

Which yields an interesting difference on arm64, in that it can't even assert *[]string.
We've considered sidestepping this by changing okx's behaviour, but it's non-trivial and dirty.
For now #1794 is merged to turn sonic off for arm64 until this is fixed.

This issue is to track the solution in sonic, and any other possible mitigations we might come up with in the meantime.

[gbjk]

Updated test to remove more superfluous distractions.
This happens on any [] any that contains pointers, and doesn't need an object wrapper.
Also stripped out assert, so we can use-as is with sonic team.

[gbjk]

Raised bytedance/sonic#750

[gbjk]

Raised bytedance/sonic#758

[gbjk]

Raised bytedance/sonic#750

First bug confirmed fixed on current (unreleased) main.

[gbjk]

Raised bytedance/sonic#758

Second bug confirmed fixed on unreleased main.