The LIT test cases were migrated with the script provided by
Nikita Popov.
No manual changes were made. Committed without review since
no functional changes, after consultation with uweigand.
As of b1d8576 there is middle-end support for STRICT_[SU]INT_TO_FP,
so this patch adds SystemZ back-end support as well.
The patch is SystemZ target specific except for adding SD patterns
strict_[su]int_to_fp and any_[su]int_to_fp to TargetSelectionDAG.td
as usual.