d: Fix closure fields don't get same alignment as local variable [PR109144]

Local variables with both non-local references and explicit alignment
did not propagate their alignment to either the closure field or closure
frame type, resulting in the closure being misaligned. This is now
correctly set-up when building the frame type.

	PR d/109144

gcc/d/ChangeLog:

	* d-codegen.cc (build_frame_type): Set frame field and type alignment.

gcc/testsuite/ChangeLog:

	* gdc.dg/torture/pr109144.d: New test.