## What changes were proposed in this pull request?
When application contains large amount of shuffle blocks. NodeManager requires lots of memory to keep metadata(`FileSegmentManagedBuffer`) in `StreamManager`. When the number of shuffle blocks is big enough. NodeManager can run OOM. This pr proposes to do lazy initialization of `FileSegmentManagedBuffer` in shuffle service.

## How was this patch tested?

Manually test.

Author: jinxing <jinxing6042@126.com>

Closes #17744 from jinxing64/SPARK-20426.