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/r956_modqual_mq_f64_i64_destr/case.ww

@@ -0,0 +1,15 @@
+//ww:run
+package myf;
+export fn frexp(n: f64) (f64, i64) = {
+	if (n == 0.0) { return (0.0, 0i64); };
+	return (n, 1i64);
+};
+package main;
+import myf;
+export fn main() i32 = {
+	let (frac, exp) = myf.frexp(8.0);
+	let g: f64 = frac + 1.0;
+	if (g != 9.0) { return 1; };
+	if (exp != 1i64) { return 2; };
+	return 0;
+};