test: add testcases from stdlib for float parser

[tdakkota]

Updates #14

[codecov]

Codecov Report

Merging #37 (6782d83) into main (98f3014) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main       #37   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           33        33           
  Lines         2265      2265           
=========================================
  Hits          2265      2265           

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