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/r921_amp_def_array/case.ww

@@ -0,0 +1,5 @@
+//ww:run-exit 18
+package main;
+def A: [3]i64 = [18i64, 11i64, 0i64];
+fn rd(p: *[3]i64) i64 = { let q: *i64 = p: *i64; return *q; };
+export fn main() i32 = { return rd(&A): i32; };