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/r691_ptr_field_chained_slice_arg/case.ww

@@ -0,0 +1,14 @@
+//ww:run-exit 42
+package main;
+type inner = struct { sl: []u8, pad: i32 };
+type outer = struct { i: *inner, tag: i32 };
+fn slen(s: []u8) i32 = { return s.len: i32; };
+fn scap(s: []u8) i32 = { return s.cap: i32; };
+fn sfirst(s: []u8) i32 = { return s[0]: i32; };
+fn main() i32 = {
+	let arr: [8]u8; arr[0] = 17u8; let inn: inner;
+	inn.sl.ptr = &arr[0]; inn.sl.len = 3; inn.sl.cap = 8;
+	let o: outer; o.i = &inn; o.tag = 0;
+	if (slen(o.i.sl) != 3) { return 1; }; if (scap(o.i.sl) != 8) { return 2; };
+	if (sfirst(o.i.sl) != 17) { return 3; }; return 42;
+};