advapi32/tests: Fix some test failures on NT4.

dlls/advapi32/tests/security.c

@@ -1728,6 +1728,8 @@ static void test_LookupAccountName(void)
     sid_use = 0xcafebabe;
     SetLastError(0xdeadbeef);
     ret = LookupAccountNameA(NULL, NULL, NULL, &sid_size, NULL, &domain_size, &sid_use);
+    if (!ret && GetLastError() != ERROR_NONE_MAPPED)
+    {
         ok(!ret, "Expected 0, got %d\n", ret);
         ok(GetLastError() == ERROR_INSUFFICIENT_BUFFER,
            "Expected ERROR_INSUFFICIENT_BUFFER, got %d\n", GetLastError());
@@ -1748,6 +1750,12 @@ static void test_LookupAccountName(void)
            account, domain);
         ok(sid_use == SidTypeDomain, "Expected SidTypeDomain (%d), got %d\n", SidTypeDomain, sid_use);
 
+        HeapFree(GetProcessHeap(), 0, psid);
+        HeapFree(GetProcessHeap(), 0, domain);
+    }
+    else
+        win_skip("NULL account name doesn't work on NT4\n");
+
     /* try an invalid account name */
     SetLastError(0xdeadbeef);
     sid_size = 0;
@@ -1770,9 +1778,6 @@ static void test_LookupAccountName(void)
        "Expected RPC_S_SERVER_UNAVAILABLE or RPC_S_INVALID_NET_ADDR, got %d\n", GetLastError());
     ok(sid_size == 0, "Expected 0, got %d\n", sid_size);
     ok(domain_size == 0, "Expected 0, got %d\n", domain_size);
-
-    HeapFree(GetProcessHeap(), 0, psid);
-    HeapFree(GetProcessHeap(), 0, domain);
 }
 
 static void test_security_descriptor(void)