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/r705_call_tail4/case.ww

@@ -0,0 +1,4 @@
+//ww:run-exit 35
+package main;
+type inner = struct { a: i32, b: i32, c: i32 }; type outer = struct { m: inner, x: i64 }; fn mki() inner = { return inner { a = 4, b = 5, c = 6 }; };
+fn main() i32 = { let o: outer = outer { m = mki(), x = 20i64 }; return (o.m.a: i64 + o.m.b: i64 + o.m.c: i64 + o.x): i32; };