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/r75_modparam_same_module_same_leaf/case.ww

@@ -0,0 +1,20 @@
+//ww:run
+package main;
+fn variadic_foo(a: i32, xs: i32...) i32 = {
+	return a + xs.len;
+};
+fn scalar_foo(a: i32, n: (u8 | []u8)) i32 = {
+	match (n) {
+	case let c: u8 => return a + (c: i32);
+	case let s: []u8 => return a + s.len;
+	};
+	return 0;
+};
+export fn main() i32 = {
+	let n: (u8 | []u8) = 5u8;
+	let a: i32 = variadic_foo(1, 2, 3, 4);
+	let b: i32 = scalar_foo(10, n);
+	if (a != 4) { return 30; };
+	if (b != 15) { return 31; };
+	return 0;
+};