Match bc_type dummy shapes to the (1:num_dims, 1:2) actual #2070

The pre_process and simulation data-output routines declared bc_type as
an explicit-shape dimension(1:num_dims, -1:1) dummy, three columns wide,
while every actual is allocated (1:num_dims, 1:2). The callee could
index past the end of the actual through sequence association.

pre_process forwards bc_type to routines that expect (1:num_dims, 1:2),
so declare it with that shape. The simulation routines never use
bc_type, so drop the argument from s_write_data_files and the serial and
parallel writers.

No change to results; the debug CPU test suite passes unchanged.

A fix for this is already written. The pull request was closed only to reduce the number of simultaneously open PRs from this author, not because the work was rejected or found incorrect.

• Closed PR: Match bc_type dummy shapes to the (1:num_dims, 1:2) actual #1996
• Branch: fix/bc-type-dummy-shape on the sbryngelson fork, at 6d82d2ebfb
• Reopening needs no force-push and no rebase: gh pr reopen 1996 -R MFlowCode/MFC

Tracked with the pr-to-do label so the whole set is discoverable together.

Filed with Claude Code.