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/r681_ptr_arr_str_write/case.ww

@@ -0,0 +1,4 @@
+//ww:run-exit 5
+package main;
+type nd = struct { a: i32, b: i32, name: str };
+fn main() i32 = { let v: nd; v.a = 0; v.b = 0; v.name = "old"; let stk: [16]*nd; stk[0] = &v; stk[0].name = "hello"; return stk[0].name.len: i32; };