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_nested_three/case.ww

@@ -0,0 +1,17 @@
+//ww:run-exit 6
+package main;
+fn main() i32 = {
+	let x: i32 = 1;
+	let s1: i32 = x;
+	let s2: i32 = 0;
+	let s3: i32 = 0;
+	{
+		let x: i32 = 2;
+		s2 = x;
+		{
+			let x: i32 = 3;
+			s3 = x;
+		};
+	};
+	return s1 + s2 + s3;
+};