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/r777_fprintf_stream/case.ww

@@ -0,0 +1,23 @@
+//ww:run-exit 46
+// Migrated from 777_fmt_handle_run row fprintf_stream.
+package main;
+import os;
+import fmt;
+import io;
+import memio;
+export fn main() i32 = {
+    let buf: [16]u8;
+    let st: memio.stream = memio.fixed(buf[0:16]);
+    let s: io.stream = &st.vt;
+    let wr = fmt.fprintf(s, "v={}\n", 42i64);
+    let nw: size = 0;
+    match (wr) {
+    case let n: size => { nw = n; };
+    case io.error => { return 91; };
+    };
+    if (nw != 5: size) { return 94; };
+    let view: str = memio.string(&st);
+    if (view.len != 5) { return 93; };
+    if (view[0] != 118u8 || view[1] != 61u8 || view[2] != 52u8 || view[3] != 50u8 || view[4] != 10u8) { return 95; };
+    return 46;
+};