message: Change tests for index based insensitive searches to use the index directly.
diff: @@ -1845,7 +1845,7 @@ TEST_TYPES(StringIndex_45, non_nullable, nullable)
  ref_type ref = StringColumn::create(Allocator::get_default());
  StringColumn col(Allocator::get_default(), ref, nullable);
  - col.create_search_index();
  + const StringIndex& ndx = *col.create_search_index();
  std::string a4 = std::string(4, 'a');
  std::string A5 = std::string(5, 'A');
  @@ -1855,7 +1855,7 @@ TEST_TYPES(StringIndex_45, non_nullable, nullable)
  ref_type results_ref = IntegerColumn::create(Allocator::get_default());
  IntegerColumn res(Allocator::get_default(), results_ref);
  - col.find_all(res, A5, 0, realm::npos, true);
  + ndx.find_all(res, A5.c_str(), true);
  CHECK_EQUAL(res.size(), 0);
  res.destroy();
  @@ -1896,7 +1896,7 @@ TEST_TYPES(StringIndex_Insensitive_Fuzz, non_nullable, nullable)
  col.add(str);
  }
  - col.create_search_index();
  + const StringIndex& ndx = *col.create_search_index();
  for (size_t t = 0; t < 1000; t++) {
  std::string needle = create_random_a_string(max_str_len);
  @@ -1904,7 +1904,7 @@ TEST_TYPES(StringIndex_Insensitive_Fuzz, non_nullable, nullable)
  ref_type results_ref = IntegerColumn::create(Allocator::get_default());
  IntegerColumn res(Allocator::get_default(), results_ref);
  - col.find_all(res, needle, 0, realm::npos, true);
  + ndx.find_all(res, needle.c_str(), true);
  // Check that all items in 'res' point at a match in 'col'
  auto needle_upper = case_map(needle, true);
  @@ -1954,7 +1954,7 @@ TEST_TYPES(StringIndex_Insensitive_VeryLongStrings, non_nullable, nullable)
  ref_type results_ref = IntegerColumn::create(Allocator::get_default());
  IntegerColumn results(Allocator::get_default(), results_ref);
  - col.find_all(results, long1, 0, realm::npos, true);
  + ndx.find_all(results, long1.c_str(), true);
  CHECK_EQUAL(results.size(), 4);
  results.clear();
  ndx.find_all(results, long2.c_str(), true);
  