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/r921_amp_def_float/case.ww

@@ -0,0 +1,5 @@
+//ww:run-exit 50
+package main;
+def D: f64 = 0.5;
+fn rd(p: *f64) f64 = { return *p; };
+export fn main() i32 = { return (rd(&D) * 100.0): i32; };