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/r630_global_slice_reassign/case.ww

@@ -0,0 +1,10 @@
+//ww:run-exit 106
+package main;
+let dst: []u8;
+let src: []u8;
+fn main() i32 = {
+	let p: *u64 = (&src): *u64;
+	p[0] = 0x1000u64; p[1] = 7u64; p[2] = 99u64;
+	dst = src;
+	return dst.len: i32 + dst.cap: i32;
+};