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/r650_value_3deep/case.ww

@@ -0,0 +1,6 @@
+//ww:run-exit 7
+package main;
+type a3 = struct { a: i32 };
+type a2 = struct { a: a3 };
+type a1 = struct { a: a2 };
+fn main() i32 = { let v: a1; v.a.a.a = 7; return v.a.a.a; };