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/r811_plain_read/case.ww

@@ -0,0 +1,4 @@
+//ww:run-exit 42
+package main;
+type pt = struct { x: size, y: size };
+export fn main() i32 = { let p = pt { x = 4: size, y = 2: size }; return (p.x * 10 + p.y): i32; };