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/r78_alias_narrow_deref_store/case.ww

@@ -0,0 +1,6 @@
+//ww:run-exit 42
+package main;
+type errno = !i32;
+type box = struct { data: [3]u64 };
+fn store(v: errno) box = { let b: box; b.data[0] = 0xFFFFFFFF00000000u64; let p = (&b.data): *errno; *p = v; return b; };
+export fn main() i32 = { let r = store(7i32: errno); let hi: u64 = r.data[0] >> 32u64; if (hi == 0u64) { return 7; }; return 42; };