test: migrate Fam13 misc checker/coercion value tests to @test (#5-C6)

Final fold-2 chunk. The 12 Fam13 single-file value drivers move from
test/wcc/*_run.c into in-language @test row-tables under test/lang/:

- value rows -> test/lang/*_test.ww (12 files)
- reject rows -> runww //ww:error carriers (13, dual-stage non-vacuous)
- nullable abort rows -> runww //ww:run-exit 1 carriers (3)
- 953_globalslice_arg -> _runonly (cs!=ww checker divergence, #28)
- 788 value_not_type_neg + 953_arrlit_slice reject_assign kept as slim
  rc-only .c pins (divergent-diag dual-reject, mutation-gated); 788 #29

Coverage parity verified row-by-row vs each retired driver; advisor-
ratified carve taxonomy; two-round reviewed. Floor ratchet follows.

test/wcc/data/nullable_asrt_void_fail/case.ww

@@ -0,0 +1,14 @@
+//ww:run-exit 1
+// #17 (F4) carrier: `e as T` on a null (*int|void) operand must ABORT (exit 1),
+// not silently pass. Hare guarantees a failed type-assert calls rt::abort (drew)
+// — not a row in @test (an abort kills `ww test`). The clean twin asrt_ptr_ok in
+// test/lang/nullable_assert_test.ww carries the abort-arm byte-id (ken: ww emits
+// the check-and-abort arm INLINE, so a wwstage regression diverges that twin);
+// the non-redundant dimension here is the RUNTIME abort. Underlying fix was
+// wwstage cgen (cgtypeassert nullable arm). From 949_nullable_assert_run.c.
+package main;
+export fn main() i32 = {
+	let p: (*int|void) = void;
+	let q = p as *int;
+	return 50;
+};