test/lang: absorb retired-carrier coverage

local_zeroinit_test.ww takes the 840/944 zero-init seam (dirty-frame
prime and probe share one @test because the runtime forks per test);
alias_cgen_b6, alloc_nested_field, array_static_init, and
strarray_static gain the rows their retired wrappers held; the
remaining files re-point reject-row citations at the r788_* and
stage-matrix fixtures.

test/lang/arrlit_slice_test.ww

@@ -1,8 +1,7 @@
 // arrlit_slice_test — #25/#31: a one-step array-LITERAL initialiser for a SLICE
 // local (`let xs: []T = [..]`). Migrated from test/wcc/953_arrlit_slice_run.c
-// (value rows; cs==ww byte-id rides T2). Reject rows (out-of-range element +
-// the three non-let-borrow contexts) stay as runww //ww:error carriers under
-// test/wcc/data/.
+// (value rows; cs==ww byte-id rides T2). Reject rows, including the
+// stage-asymmetric assignment diagnostic, live under test/wcc/data/.
 //
 // #31 (silent cs!=ww): the borrow wrapped the un-addressable arrlit directly,
 // so .ptr pointed at garbage (xs[1] returned 1, not 20; []u8/[]str SEGV). #25