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_declns_builtin_redecl/case.ww

@@ -0,0 +1,10 @@
+//ww:run-exit 7
+package main;
+type nomem = !void;
+fn g() (i32 | nomem) = { return 7; };
+export fn main() i32 = {
+	match (g()) {
+	case let v: i32 => return v;
+	case nomem => return 99;
+	};
+};