[libc++][test] update MinSequenceContainer.h to make one more test pass on MSVC STL (#158344)

Continues #140287

`from_range_t` constructor is needed by MSVC STL to pass
`std/containers/container.adaptors/flat.set/flat.set.cons/range.pass.cpp`.

The rest are added to complete the container according to
#140287 (review).

Author: AlexGuteniev

libcxx/test/support/MinSequenceContainer.h

@@ -29,13 +29,23 @@ struct MinSequenceContainer {
   template <class It>
   explicit TEST_CONSTEXPR_CXX20 MinSequenceContainer(It first, It last) : data_(first, last) {}
   TEST_CONSTEXPR_CXX20 MinSequenceContainer(std::initializer_list<T> il) : data_(il) {}
+  template <class Range>
+  TEST_CONSTEXPR_CXX20 MinSequenceContainer(std::from_range_t, Range&& rg)
+      : data_(std::from_range, std::forward<Range>(rg)) {}
+  TEST_CONSTEXPR_CXX20 MinSequenceContainer(size_type n, T value) : data_(n, value) {}
+
+  MinSequenceContainer& operator=(std::initializer_list<T> il) { data_ = il; }
 
   template <class It>
   TEST_CONSTEXPR_CXX20 void assign(It first, It last) {
     data_.assign(first, last);
   }
   TEST_CONSTEXPR_CXX20 void assign(std::initializer_list<T> il) { data_.assign(il); }
   TEST_CONSTEXPR_CXX20 void assign(size_type n, value_type t) { data_.assign(n, t); }
+  template <class Range>
+  TEST_CONSTEXPR_CXX20 void assign_range(Range&& rg) {
+    data_.assign_range(std::forward<Range>(rg));
+  }
   TEST_CONSTEXPR_CXX20 iterator begin() { return iterator(data_.data()); }
   TEST_CONSTEXPR_CXX20 const_iterator begin() const { return const_iterator(data_.data()); }
   TEST_CONSTEXPR_CXX20 const_iterator cbegin() const { return const_iterator(data_.data()); }
@@ -55,6 +65,14 @@ struct MinSequenceContainer {
     return from_vector_iterator(data_.insert(to_vector_iterator(p), std::move(value)));
   }
 
+  TEST_CONSTEXPR_CXX20 iterator insert(const_iterator p, size_type n, T value) {
+    return from_vector_iterator(data_.insert(to_vector_iterator(p), n, value));
+  }
+
+  TEST_CONSTEXPR_CXX20 iterator insert(const_iterator p, std::initializer_list<T> il) {
+    return from_vector_iterator(data_.insert(to_vector_iterator(p), il));
+  }
+
   template <class Range>
   TEST_CONSTEXPR_CXX20 iterator insert_range(const_iterator p, Range&& rg) {
     return from_vector_iterator(data_.insert_range(to_vector_iterator(p), std::forward<Range>(rg)));