Internal temporary Aria tables writes blocks to disk at end of query

MDEV-17070 "Table corruption.." fix caused a side effect that Aria internal temporary tables would write all changed blocks to disk when table was closed (at end of query).

This bug was introduced 2019 and was not noticed until I did some benchmarks and noticed that Aria_pagecache_writes increased for queries using temporary tables even if I tried to increase aria_pagecache_buffer_size.

This is now fixed.
As part of the fix, I also removed an extra not needed block read when the internal temporary table was open.

These fixes give a performance increase when using big internal temporary tables or using many concurrent queries that are using internal temporary tables to store the result.