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/r828_arrlit_arg_exact/case.ww

@@ -0,0 +1,10 @@
+//ww:run-exit 20
+// Migrated from 828_overlong_arrlit row arg_exact.
+package main;
+fn g(a: [2]int) int = {
+	return a[1];
+};
+export fn main() i32 = {
+	let v: [2]int = [10, 20];
+	return g(v): i32;
+};