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/r812_alias_twolevel_assign/case.ww

@@ -0,0 +1,5 @@
+//ww:run
+package main;
+type ali = base;
+type base = struct { a: size, b: size, c: size };
+export fn main() i32 = { let a: ali; a.a = 4; a.b = 9; a.c = 13; let b: ali; b.a = 0; b.b = 0; b.c = 0; b = a; if (b.a != 4) { return 1; }; if (b.b != 9) { return 2; }; if (b.c != 13) { return 3; }; return 0; };