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/r744_letcopy_tri_i32/case.ww

@@ -0,0 +1,13 @@
+//ww:run
+package main;
+import os;
+type tri = struct { a: i32, b: i32, c: i32 };
+fn produce() i32 = {
+	let p1: tri = tri{a=11, b=22, c=33};
+	let p2: tri = p1;
+	if (p2.a != 11) { return 11; };
+	if (p2.b != 22) { return 12; };
+	if (p2.c != 33) { return 13; };
+	return 0;
+};
+export fn main() i32 = { os.exit(produce()); };