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/r701_trip_i64_reassign_lit/case.ww

@@ -0,0 +1,8 @@
+//ww:run-exit 84
+package main;
+type trip = struct { x: i64, y: i64, z: i64 };
+fn main() i32 = {
+	let s: trip = trip { x = 0i64, y = 0i64, z = 0i64 };
+	s = trip { x = 14i64, y = 28i64, z = 42i64 };
+	return (s.x + s.y + s.z): i32;
+};