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/r74_size_leaf_baseline/case.ww

@@ -0,0 +1,16 @@
+//ww:run
+package main;
+type tagged = (rune | void);
+fn pickrune(x: tagged) i32 = {
+	match (x) {
+	case let r: rune => return r: i32;
+	case void => return 0;
+	};
+	return 0;
+};
+export fn main() i32 = {
+	let v: tagged = 'A';
+	let r: i32 = pickrune(v);
+	if (r != 65) { return 11; };
+	return 0;
+};