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/r71_arrlit_i64/case.ww

@@ -0,0 +1,6 @@
+//ww:run-exit 6
+package main;
+fn main() i32 = {
+	let a: [3]i64 = [1i64, 2i64, 3i64];
+	return (a[0] + a[1] + a[2]): i32;
+};