Hi,

this patch fixes an 8 regression in an openacc testcase.

The regression was introduced by r250925, a fix for PR78266, a bug in 
the handling of a loop with iteration variable type range smaller than 
the size of the parallel dimension the loop is assigned to.

The fix for the regression is to apply the r250925 fix (in 
expand_oacc_for) to expand_oacc_collapse_init as well.

Build and reg-tested on x86_64 with nvptx accelerator.

Committed to stage4 trunk.

Thanks,
- Tom