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/r630_global_struct_compound/case.ww

@@ -0,0 +1,6 @@
+//ww:run-exit 42
+package main;
+type counter = struct { n: i64 };
+let c: counter;
+fn bump(d: i64) void = { c.n += d; };
+fn main() i32 = { bump(10i64); bump(15i64); bump(17i64); return c.n: i32; };