Disagg: evict read node local cache when the file is not used anymore

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

insert some table and select count(*) using tiflash. deploy tiflash with s3 using minio
set read node remote cache 800G

2. What did you expect to see? (Required)

The remote cache can be evict and tiflash run stable

3. What did you see instead (Required)

The remote cache can't not be evicted

[2023/04/18 13:29:38.322 +08:00] [WARN] [PathCapacityMetrics.cpp:306] ["No available space for path: /data0/tiflash/cache, capacity: 800.00 GiB, used: 802.70 GiB"] [thread_id=2313]
[2023/04/18 13:29:48.323 +08:00] [WARN] [PathCapacityMetrics.cpp:306] ["No available space for path: /data0/tiflash/cache, capacity: 800.00 GiB, used: 802.70 GiB"] [thread_id=2313]
[2023/04/18 13:29:58.324 +08:00] [WARN] [PathCapacityMetrics.cpp:306] ["No available space for path: /data0/tiflash/cache, capacity: 800.00 GiB, used: 802.70 GiB"] [thread_id=2313]
[2023/04/18 13:30:08.325 +08:00] [WARN] [PathCapacityMetrics.cpp:306] ["No available space for path: /data0/tiflash/cache, capacity: 800.00 GiB, used: 802.70 GiB"] [thread_id=2313]
[2023/04/18 13:30:18.326 +08:00] [WARN] [PathCapacityMetrics.cpp:306] ["No available space for path: /data0/tiflash/cache, capacity: 800.00 GiB, used: 802.70 GiB"] [thread_id=2313]

TiFlash seems hang when the remote cache capacity is full

4. What is your TiFlash version? (Required)

master

Reproduce the full-cache case with TiFlash, S3 and MinIO using the reported remote-cache settings, then inspect PathCapacityMetrics.cpp around line 306. Confirm that unused local cache data is evicted when capacity is reached and that TiFlash continues running without repeated no-space warnings.