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/r75_alloc_str_then_i32/case.ww

@@ -0,0 +1,5 @@
+//ww:run-exit 12
+package main;
+import rt;
+type holder = struct { s: str, n: i32 };
+fn main() i32 = { let p: *holder = alloc(holder { s = "world", n = 7 })!; return p.s.len + p.n; };