fix(HeadFile,CellBudgetFile): fix tdis reversal

[wpbonelli]

Fix #2459 and expand tests

[codecov]

Codecov Report

Attention: Patch coverage is 93.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 75.8%. Comparing base (bb9824e) to head (4e11c6b).
Report is 61 commits behind head on develop.

Files with missing lines	Patch %	Lines
flopy/utils/binaryfile/__init__.py	93.3%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #2460     +/-   ##
=========================================
+ Coverage     68.4%   75.8%   +7.4%     
=========================================
  Files          294     293      -1     
  Lines        59390   61905   +2515     
=========================================
+ Hits         40652   46962   +6310     
+ Misses       18738   14943   -3795     

Files with missing lines	Coverage Δ
flopy/utils/binaryfile/__init__.py	86.1% <93.3%> (ø)

... and 254 files with indirect coverage changes