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/r915_arr_local_nonzero/case.ww

@@ -0,0 +1,8 @@
+//ww:run-exit 1
+package main;
+export fn main() i32 = {
+	let t: [8]u16 = [0u16, 0x0800u16, 0x0801u16, 0x0803u16,
+		0x1006u16, 0x1009u16, 0x100Du16, 0x1812u16];
+	let v: u32 = (t[2]: u32);
+	return v: i32;
+};