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/r989_fmt_width_2147483648/case.ww

@@ -0,0 +1,12 @@
+//ww:run-exit 255
+package main;
+import fmt;
+import io;
+export fn main() i32 = {
+	let buf: [64]u8;
+	let r: (str | io.error) = fmt.bsprintf(buf[0:64], "{:2147483648}", 42i64);
+	match (r) {
+	case let s: str => { return 0; };
+	case let e: io.error => { return 1; };
+	};
+};