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/r709_localoff_if_shadow/case.ww

@@ -0,0 +1,12 @@
+//ww:run-exit 7
+package main;
+fn main() i32 = {
+	let a: i32 = 7;
+	let touched: i32 = 0;
+	if (a > 0i32) {
+		let a: i32 = 99;
+		touched = a;
+	};
+	if (touched != 99i32) { return 1i32; };
+	return a;
+};