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_tuple/case.ww

@@ -0,0 +1,11 @@
+//ww:run-exit 51
+// Migrated from 825_errfirst_union_try row errfirst_tuple.
+package main;
+type e = !i32;
+type ut = (e | (u16, u16));
+fn ok() ut = { return (300u16, 7u16); };
+export fn main() i32 = {
+	let t = ok()!;
+	let (a, b) = t;
+	return (a: i32) + (b: i32);
+};