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_arr_index/case.ww

@@ -0,0 +1,8 @@
+//ww:run-exit 18
+package main;
+fn rd(p: *i64) i64 = { return *p; };
+export fn main() i32 = {
+	let a: [3]i64 = [5i64, 18i64, 9i64];
+	let p: *i64 = &a[1];
+	return rd(p): i32;
+};