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/r660_bang_i32_deref_widen/case.ww

@@ -0,0 +1,5 @@
+//ww:run-exit 42
+package main;
+type myinv = !i32;
+fn setneg(p: *myinv) void = { *p = -16i64: myinv; };
+fn main() i32 = { let x: myinv = 0i64: myinv; setneg(&x); let z: i64 = x: i64; if (z == -16i64) { return 42; }; return 0; };