Fix crash bugs found through fuzz testing

[akrennmair]

This PR fixes a number of crashe bugs that were found through fuzz testing of the file reader. The auto-generated files were regenerated using the thrift compiler from Apache Thrift's latest master.

[codecov-commenter]

Codecov Report

Merging #86 (5535ed6) into master (5f8d67a) will increase coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #86      +/-   ##
==========================================
+ Coverage   86.53%   86.57%   +0.04%     
==========================================
  Files          48       48              
  Lines        9774     9774              
==========================================
+ Hits         8458     8462       +4     
+ Misses        952      950       -2     
+ Partials      364      362       -2     

Impacted Files	Coverage Δ
file_reader.go	74.43% <0.00%> (+1.50%)	⬆️
file_meta.go	33.33% <0.00%> (+6.66%)	⬆️

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