test: port the xmod same-leaf collision carriers to corpus fixtures

752_modparam_callee.c -> r752_modparam_xmod_variadic_vs_scalar,
  r752_modparam_variadic_no_collision (run; alpha/beta module dirs)
784_xmod_alias_struct_collide_run.c -> r784_xmod_alias_struct_collide
  (run-exit 42), r784_xmod_alias_struct_symmetric (21),
  r784_xmod_alias_control (30) (sa/sb module dirs)
793_xmod_struct_argpush_collide_run.c -> r793_xmod_argpush_
  {recvpush_t16 107, fieldread_t16 107, combined_t16 114,
  recvpush_t12 6} (m1/m2 module dirs)
797_xmod_struct_field_layout_collide_run.c -> r797_xmod_layout_
  {ptrread_t16 107, letcopy_t16 107, addrptr_pq 10, addrval_pq 10,
  ptrwrite_t16 109, valwrite_t16 109} (m1/m2) + r797_nestfill_box (66)

r770-style sibling module dirs express the trees; the fixture corpus
runs both drivers natively (784's wwstage-build-only leg upgrades to
build+run) and test-data-byteid owns each carrier's aggregated per-
package .s compare (letcopy_t16's real discriminator). All 16 probed
green on both stages including per-package byte identity.

test/wcc/data/r752_modparam_variadic_no_collision/alpha/alpha.ww

@@ -0,0 +1,8 @@
+// sole variadic callee for the r752 no-collision control.
+package alpha;
+export fn sum(a: i32, xs: i32...) i32 = {
+	let t: i32 = a;
+	let i: i32 = 0;
+	for (i < xs.len) { t += xs[i]; i += 1; };
+	return t;
+};

test/wcc/data/r752_modparam_variadic_no_collision/case.ww

@@ -0,0 +1,9 @@
+//ww:run
+// migrated from test/wcc/752_modparam_callee.c: control — variadic callee in one module only; the N_IDENT arm stays on bare fnparamslookup.
+package main;
+import alpha;
+export fn main() i32 = {
+	let r: i32 = alpha.sum(1, 2, 3, 4);
+	if (r != 10) { return 40; };
+	return 0;
+};