HarmonyOS 直播间进去后会有大量用TextDecoder解析array到utf8 string的需求，现在几乎必现ANR

参考示例：

import { flexModelCustomizer, FlexModelTextDecoder, KmpJsonAdapter } from '@live/live_kmp/IndexFlexModel'
import util from '@ohos.util'
import { stringify } from 'json-bigint'
class CustomTextDecoderImpl implements FlexModelTextDecoder {
  private readonly textDecoder = new util.TextDecoder()
  decodeUtf8(byteArray: Int8Array, start: number, end: number): string {
    return this.textDecoder.decodeWithStream(new Uint8Array(byteArray.buffer, start, end - start))
  }
}
flexModelCustomizer.get().customTextDecoder = new CustomTextDecoderImpl()

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