fix(array): remove 64bit refcount misalignments (#5390)

Invoking atomic operations in the reference counters resulted in an alignment panic in armv7, due to them not being 64bit aligned.

Declaring them first in the struct solved it.

See https://pkg.go.dev/sync/atomic#pkg-note-BUG fore more details

For context: I already fixed a similar issue at #4676

array/array.go

@@ -218,10 +218,10 @@ func (a *String) IsConstant() bool {
 }
 
 type stringValue struct {
+	rc   int64
 	data []byte
 
 	mem arrowmem.Allocator
-	rc  int64
 }
 
 func (v *stringValue) Retain() {

array/builder.go

@@ -10,13 +10,13 @@ import (
 )
 
 type StringBuilder struct {
+	refCount     int64
 	builder      *array.BinaryBuilder
 	mem          memory.Allocator
 	value        *stringValue
 	length       int
 	capacity     int
 	dataCapacity int
-	refCount     int64
 }
 
 func NewStringBuilder(mem memory.Allocator) *StringBuilder {