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/r776_dynamicfrom_alt_rw/case.ww

@@ -0,0 +1,23 @@
+//ww:run-exit 44
+// Migrated from 776_memio_vstream_run row dynamicfrom_alt_rw.
+package main;
+import memio;
+import io;
+import os;
+export fn main() i32 = {
+    let seed: [4]u8;
+    seed[0] = 1u8; seed[1] = 2u8; seed[2] = 3u8; seed[3] = 4u8;
+    let st: memio.stream = memio.dynamicfrom(seed[0:4]);
+    let s: io.stream = &st.vt;
+    let out: [4]u8;
+    let rd = io.read(s, out[0:4]);
+    let rn: size = 0;
+    if (rd is size) { rn = rd as size; };
+    let extra: [2]u8;
+    extra[0] = 99u8; extra[1] = 100u8;
+    let wr = io.write(s, extra[0:2]);
+    let wn: size = 0;
+    if (wr is size) { wn = wr as size; };
+    if (rn == 4: size && wn == 2: size && out[0] == 1u8 && out[3] == 4u8) { return 44; };
+    return 99;
+};