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/r957_assert_imported_mod/case.ww

@@ -0,0 +1,9 @@
+//ww:run-exit 42
+package m;
+export fn f() i32 = {
+	assert(3 > 2, "m.f invariant");
+	return 42;
+};
+package main;
+import m;
+export fn main() i32 = { return m.f(); };