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_f64_str_i32/case.ww

@@ -0,0 +1,5 @@
+//ww:run-exit 13
+package main;
+import rt;
+type holder = struct { f: f64, s: str, n: i32 };
+fn main() i32 = { let p: *holder = alloc(holder { f = 1.5f64, s = "abc", n = 10 })!; return p.s.len + p.n; };