Always write a whole page at a time when writing compressed data

[benjaminwinger]

A fix from #2408 which ended up breaking windows CI in #2304.

If data is compressed to 0 bytes, it would end up writing nothing, and if the data is at the end of the file the next time the file is opened it will read the number of pages as one less, triggering exceptions when attempting to read the last page.

Ideally we shouldn't be reading at all when data is compressed to nothing, but that can be addressed later.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (bb159fe) 90.44% compared to head (dbbc0e6) 90.42%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2438      +/-   ##
==========================================
- Coverage   90.44%   90.42%   -0.02%     
==========================================
  Files        1020     1020              
  Lines       36641    36640       -1     
==========================================
- Hits        33139    33133       -6     
- Misses       3502     3507       +5     

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