The debug options passed down from the public ShConstruct* functions to
internal code is unused. This change removes the internal debugOptions
fields and attempts to make it more obvious these fields are not used.
This change does not change the public-facing interface.
This change also adds the -Wshorten-64-to-32 warning to the StandAlone
build in order to avoid unwanted 64-to-32 bit conversions in the future.
Closes#3348.
