test: port 915/949 module-global access carriers to corpus fixtures

915_arr_module_index_run.c -> r915_arr_mod_idx0 (run), r915_arr_mod_
  idx2 (run-exit 1), r915_arr_mod_idx4 (run-exit 6); the single-file
  rows were already owned by r915_arr_local_* + test-data-byteid.
949_xmod_fnptr_const_run.c -> r949_xmod_fnptr_const_table (run),
  r949_xmod_fnptr_wrong_sig, r949_xmod_fnptr_nonfn_dotted (error
  'not assignable' both stages).

The 915 module rows upgrade from 994-delegated to per-fixture cs==ww
byte identity; 949's 2-file -I tree was not load-bearing — inline
packages exercise the same N_DOT &mod.fn mangle (mafn(leaf, module)).

test/wcc/data/r949_xmod_fnptr_wrong_sig/case.ww

@@ -0,0 +1,8 @@
+//ww:error "not assignable"
+// migrated from test/wcc/949_xmod_fnptr_const_run.c: cross-module &fn with a mismatched signature must not satisfy the declared *fn slot.
+package cc;
+export fn isa(c: rune) bool = { return c == 'a'; };
+package main;
+import cc;
+const t: [](str, *fn(x: i32) i32) = [(":a", &cc.isa)];
+export fn main() i32 = { return len(t): i32; };