[RemoveDIs] Make verify-uselistorder preserve the input debug info format (#87789)

Verify-uselistorder wants to take some input IR and verify that the
uselist order is stable after roundtripping to bitcode and assembly.
This is disrupted if the file is converted between the new and old debug
info formats after parsing - while there's no functional difference, the
change to the in-memory representation of the IR modifies the uselist.
This patch changes verify-uselistorder to not convert input files
between debug info formats by default, preventing changes from being
made to the file being checked. In addition, this patch makes it so that
when we _do_ print IR in the new debug info format to bitcode or
assembly, we delete any lingering debug intrinsic declarations, ensuring
that we don't write uselist entries for them.