test: migrate defdim len/cap family to test/lang @test, retire C twins (fold-2)

Continue fold-2: migrate drew's Family 2 (def-dimensioned array len/cap/slice
resolution) from bespoke build+run C twins to test/lang @test, retiring each
twin in the same commit. Runtime coverage MOVES from $(TESTS) to test-lang (T1
runs+asserts via `ww test`) + test-lang-byteid (T2 keeps cs==ww .s byte-id);
coverage is preserved, the $(TESTS) headline drops 3 (425->422). All asserts are
primitive int comparisons (no fmt/strconv in the assert path); the defcap rows
poison cap != len and assert both words so a dropped cap word FAILS.

  989_defdim_field_run.c    -> defdim_field_test.ww    (`.len` field-read on a def-dim [MAX]T resolves from the type table: local/let-global/def cgdot arms + sum)
  989_defdim_slice_run.c    -> defdim_slice_test.ww    (slicing a def-dim [MAX]T resolves len AND cap from the type table: default-hi + cgbasecap, local+global)
  989_defdim_argslice_run.c -> defdim_argslice_test.ww (def-dim slice passed as a call arg resolves default-hi len in the N_SLICE arg-push arms; litctrl pins the N_INTLIT path)

Bump LANGBYTEID_EXPECTED_MIN 31->34 to ratchet the new corpus floor.

test/lang/defdim_argslice_test.ww

@@ -0,0 +1,35 @@
+// defdim_argslice_test — passing a slice of a `def`-dimensioned array
+// (`take(buf[1:])` on `[MAX]T`) as a call argument must resolve the default-hi
+// length from the type table, the N_SLICE arg-push member of the def-dim
+// family, migrated from test/wcc/989_defdim_argslice_run.c (#56 c4). pushargsrev's
+// N_SLICE default-hi arms (local / global) only handled an N_INTLIT dim, so a
+// plain `[MAX]u8` base emitted nothing and the pushed slice header's len word
+// was left stale -- the callee read garbage (ww 135 local / 255 global). The
+// fix reads alen from the stamped array tinfo (rule-13) in both arg-push arms.
+// `take` returns s.len, so the asserted 4 IS the pushed-header length contract;
+// the litctrl row pins the N_INTLIT path so the new else-arm can't perturb it.
+// T2 (test-lang-byteid) keeps the cs==ww net the .c twin's run-compare gave.
+
+package defdim_argslice_test;
+
+def MAX: i32 = 5;
+let g: [MAX]u8 = [1, 2, 3, 4, 5];
+
+fn take(s: []u8) i32 = { return s.len: i32; };
+
+@test fn local_argslice() void = {
+	// local def-dim base: take(buf[1:]) sees len 5-1 = 4.
+	let buf: [MAX]u8 = [1, 2, 3, 4, 5];
+	assert(take(buf[1:]) == 4);
+};
+
+@test fn global_argslice() void = {
+	// global def-dim base: take(g[1:]) sees len 4.
+	assert(take(g[1:]) == 4);
+};
+
+@test fn litctrl_argslice() void = {
+	// literal-dim control: the N_INTLIT arm stays correct (no regress).
+	let buf: [5]u8 = [1, 2, 3, 4, 5];
+	assert(take(buf[1:]) == 4);
+};