[llvm] [ADT] Add `DenseMap::insert_range` (PR #133600)

[Baranov Victor via llvm-commits]

================
@@ -379,6 +379,17 @@ TEST(DenseMapCustomTest, EqualityComparison) {
   EXPECT_NE(M1, M3);
 }
 
+TEST(DenseMapCustomTest, InsertRange) {
----------------
vbvictor wrote:

Added in `llvm/unittests/ADT/DenseSetTest.cpp`

https://github.com/llvm/llvm-project/pull/133600