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_neighbor_guard/case.ww

@@ -0,0 +1,4 @@
+//ww:run
+package main;
+type pt = struct { x: size, y: size, z: size };
+export fn main() i32 = { let guard1: size = 111: size; let b: pt = pt { x = 0: size, y = 0: size, z = 0: size }; let guard2: size = 222: size; let a: pt = pt { x = 1: size, y = 2: size, z = 3: size }; b = a; if (guard1 != 111) { return 1; }; if (guard2 != 222) { return 2; }; if (b.x + b.y + b.z != 6) { return 3; }; return 0; };