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/r83_idcast_bool/case.ww

@@ -0,0 +1,12 @@
+//ww:run-exit 11
+package main;
+type u = (int | bool | str);
+fn f() u = { let x: u = true; return x: u; };
+export fn main() i32 = {
+	match (f()) {
+	case let n: int => return 70;
+	case let b: bool => return 11;
+	case let s: str => return 22;
+	};
+	return 99;
+};