[Go] Fix to not allocate to the heap when iterating over repeating groups …

[adam-talos]

…in golang 1.22

Verify by running

go build -gcflags=all=-d=loopvar=2

When compiling in Golang 1.22, the loop behavior has changed and the code generated by SBE in Go can suddenly allocate to the heap.

You can verify this by running

go build -gcflags=all=-d=loopvar=2

Before the generated could would look like

    for _, prop := range m.Entries {
        if err := prop.Encode(_m, _w); err != nil {
            return err
        }
    }

This reference to prop could potentially allocate if prop.Encode could not be inlined.

The new code that is generated uses the index to get the reference, which will not allocate.

    for i := range m.Entries {
        if err := m.Entries[i].Encode(_m, _w); err != nil {
            return err
        }
    }