test: birth test/misc + port the arrglob DATAW observer; retire 689_arrglob_nodup_run

test/misc hosts the residual mixed-shape observers (divergence pins,
stamp/stderr probes, .wwi trees) on testenv, wired into test-compiler
beside the sep/xmod/asm families; its rule declares both full
per-stage toolchains plus the wwdump twins for the coming files.
The 689 port keeps the both-driver run-exit-6 backstop and the
per-stage absolute DATAW row count (linker dedup and byte-id sweeps
are both blind to a symmetric double-emit).

test/misc/arrglob_test.ww

@@ -0,0 +1,93 @@
+package arrglob_test;
+
+// #12: a no-init module-level array global emits its zero-fill DATAW
+// row EXACTLY ONCE. Port of the retired native carrier
+// test/wcc/689_arrglob_nodup_run.c; every assertion preserved. The
+// wwstage bug was a SIZE-keyed (sz == 24) str-fallback arm matching a
+// [3]u64 global on top of the TY_ARRAY arm — two identical rows the
+// linker deduped, so runtime and byte-id-only sweeps stayed blind to
+// the absolute count: the per-stage count == 1 is the unowned claim.
+//
+// Legs: build+run exit 6 through both driver stages (correctness
+// backstop), then per-stage `DATAW main.g(SB)` occurrence count == 1
+// over the emitted .s (both stages emitting 2 identical rows would
+// pass a byte-id sweep).
+
+import os;
+import os.exec;
+import strings;
+import testenv;
+import time;
+
+fn fail(label: str, why: str) void = {
+	let m: str = strings.concat("arrglob FAIL: ", label, " -- ", why,
+		"\n");
+	os.write(2, m.ptr, m.len: u64);
+	assert(false);
+};
+
+fn tmo() time.duration = {
+	return (240i64 * (time.second: i64)): time.duration;
+};
+
+fn src() str = {
+	return strings.concat(
+	"package main;\n",
+	"let g: [3]u64;\n",
+	"export fn main() i32 = {\n",
+	"	g[0] = 1; g[1] = 2; g[2] = 3;\n",
+	"	return (g[0] + g[1] + g[2]): i32;\n",
+	"};\n");
+};
+
+fn runcode(dir: str, name: str, argv: []str) i32 = {
+	let co: testenv.commandout;
+	testenv.runcommand(dir, dir, name, argv, tmo(), &co);
+	if (co.termination != exec.termination.EXIT) { return -1; };
+	return co.code;
+};
+
+@test fn rundrivers() void = {
+	let drvs: []str = ["ww", "ww_ww"];
+	let s: i32 = 0;
+	for (s < 2) {
+		let td: str = testenv.fresh();
+		testenv.writefile(strings.concat(td, "/t.ww"), src());
+		let av: []str = [testenv.driver(drvs[s]), "build", "-o",
+			"t", "t.ww"];
+		if (runcode(td, strings.concat("build_", drvs[s]), av) != 0) {
+			fail(drvs[s], "driver build failed");
+		};
+		let rav: []str = [strings.concat(td, "/t")];
+		if (runcode(td, strings.concat("run_", drvs[s]), rav) != 6) {
+			fail(drvs[s], "run-exit != 6");
+		};
+		testenv.clean(td);
+		s += 1;
+	};
+};
+
+@test fn datawcount() void = {
+	let tools: []str = ["w6c", "w6c_ww"];
+	let s: i32 = 0;
+	for (s < 2) {
+		let td: str = testenv.fresh();
+		testenv.writefile(strings.concat(td, "/t.ww"), src());
+		let av: []str = [testenv.driver(tools[s]), "-o",
+			strings.concat(td, "/t.s"),
+			strings.concat(td, "/t.ww")];
+		let co: testenv.commandout;
+		testenv.runcommand(td, td, tools[s], av, tmo(), &co);
+		if (co.termination != exec.termination.EXIT || co.code != 0) {
+			fail(tools[s], "compile failed");
+		};
+		let asm: str = testenv.readfile(strings.concat(td, "/t.s"));
+		let n: i32 = testenv.occurrences(asm, "DATAW main.g(SB)");
+		if (n != 1) {
+			fail(tools[s],
+				"DATAW main.g rows != 1 (double-emit #12)");
+		};
+		testenv.clean(td);
+		s += 1;
+	};
+};