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/r732_def_sibling_ref/case.ww

@@ -0,0 +1,5 @@
+//ww:run-exit 42
+package main;
+def A: i32 = 7;
+def B: i32 = A;
+fn main() i32 = { let x: i32 = B; if (x == 7) { return 42; }; return 1; };