test/wcc/data: grow the declarative compiler corpus to 1,224 fixtures

The r-prefixed waves absorb the runtime, reject, and byte-compare rows
of the migrated native carriers; each fixture is one directory with one
case.ww and a //ww:error, //ww:compile, //ww:run, or //ww:run-exit
directive covering both frontends.

test/wcc/data/r989_callarg_fn_bare/case.ww

@@ -0,0 +1,6 @@
+//ww:run-exit 7
+package main;
+type myfn = fn() int;
+fn g() int = { return 7; };
+fn use_it(f: myfn) int = { return f(); };
+export fn main() int = { return use_it(g); };