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/r710_bool_to_i8_clamp/case.ww

@@ -0,0 +1,7 @@
+//ww:run-exit 1
+package main;
+fn main() i32 = {
+	let b: bool = true;
+	let y: i8 = b: i8;
+	return (y: i32);
+};