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/r772_call_as_namedvoid/case.ww

@@ -0,0 +1,12 @@
+//ww:run-exit 42
+// Migrated from 772_typeassert_nonident row call_as_namedvoid.
+package main;
+type nv = void;
+fn f(b: bool) (size | nv) = {
+    if (b) { return void: nv; };
+    return 0: size;
+};
+export fn main() i32 = {
+    let _ = f(true) as nv;
+    return 42;
+};