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/r825_errfirst_3var/case.ww

@@ -0,0 +1,10 @@
+//ww:run-exit 99
+// Migrated from 825_errfirst_union_try row errfirst_3var.
+package main;
+type e1 = !i32;
+type e2 = !i64;
+type u3 = (e1 | e2 | u16);
+fn h() u3 = { return 99u16; };
+export fn main() i32 = {
+	return h()!: i32;
+};