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/r72_empty_alloc_call_arg/case.ww

@@ -0,0 +1,4 @@
+//ww:error "cannot infer slice element type for alloc([], n) without a type hint"
+package main;
+fn g(x: []u8) i32 = { return x.len: i32; };
+fn main() i32 = { return g(alloc([], 8u64)!); };