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/r989_cata_match_same_yield/case.ww

@@ -0,0 +1,8 @@
+//ww:run-exit 9
+package main;
+fn pick(b: bool) (i32 | str) = { if (b) { return 4; }; return "x"; };
+export fn main() i32 = {
+	let v: (i32 | str) = pick(true);
+	let r: i32 = match (v) { case i32 => yield 9; case let s: str => yield 5; };
+	return r;
+};