create-diff-object: Include string sections later

create-diff-object: Include string sections later

... when all symbols have their status and include flags processed.

Processing special sections may include additional symbols. String
sections (.rodata*) are included iff they are referenced by at least
one symbol. Thus, in order to decide if string section should be
included or not, all symbols must be evaluated first.

Signed-off-by: Pawel Wieczorkiewicz <wipawel@amazon.de>
Reported-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Tested-by: Sergey Dyasli <sergey.dyasli@citrix.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>