Don't assume nul termination in printf

Thanks ZUENS2020 for reporting.

test/format-test.cc

@@ -268,22 +268,6 @@ TEST(util_test, format_system_error) {
   fmt::format_system_error(message, EDOM, "test");
   auto ec = std::error_code(EDOM, std::generic_category());
   EXPECT_EQ(to_string(message), std::system_error(ec, "test").what());
-  message = fmt::memory_buffer();
-
-  // Check if std::allocator throws on allocating max size_t / 2 chars.
-  size_t max_size = max_value<size_t>() / 2;
-  bool throws_on_alloc = false;
-  try {
-    auto alloc = std::allocator<char>();
-    alloc.deallocate(alloc.allocate(max_size), max_size);
-  } catch (const std::bad_alloc&) {
-    throws_on_alloc = true;
-  }
-  if (!throws_on_alloc) {
-    fmt::print(stderr, "warning: std::allocator allocates {} chars\n",
-               max_size);
-    return;
-  }
 }
 
 TEST(util_test, system_error) {