Remove unused field from CompilerConfig
Rename INTERNAL to INTERNAL_ERROR
Add error code for compiler errors
Fix nth_value function
Use equals instead of == for Doubles in LiteralInterpreter
Disable DWRF String and Date statistics which are broken

The merge logic DWRF String and Date statistics are broken so the statistics
for stripes and files in DWRF can not be used for String and Date columns.
Ignore ORC and DWRF DoubleStatistics containing NaN

ORC and DWRF writer does not handle NaNs properly so any statistic involving a NaN should be ignored.