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/r71_struct_field_index_str_arg/case.ww

@@ -0,0 +1,23 @@
+//ww:run
+package main;
+fn streq(a: str, b: str) i32 = {
+	if (a.len != b.len) { return 0i32; };
+	let i: i32 = 0;
+	for (i < a.len) {
+		if (a[i] != b[i]) { return 0i32; };
+		i += 1;
+	};
+	return 1i32;
+};
+type cmd = struct { argsptr: *str, argslen: i32 };
+fn main() i32 = {
+	let xs: [2]str;
+	xs[0] = "first";
+	xs[1] = "second";
+	let c: cmd;
+	c.argsptr = &xs[0];
+	c.argslen = 2;
+	if (streq(c.argsptr[0], "first") == 0i32) { return 1; };
+	if (streq(c.argsptr[1], "second") == 0i32) { return 2; };
+	return 0;
+};