Refactor swisstable copy/move assignment to fix issues with allocator propagation and improve performance.

Correctness:
- We use swap to implement copy assignment and move assignment, which means that allocator propagation in copy/move assignment depends on `propagate_on_container_swap` in addition to `propagate_on_container_copy_assignment`/`propagate_on_container_move_assignment`.
- In swap, if `propagate_on_container_swap` is `false` and `get_allocator() != other.get_allocator()`, the behavior is undefined (https://en.cppreference.com/w/cpp/container/unordered_set/swap) - we should assert that this UB case isn't happening. For this reason, we also delete the NoPropagateOn_Swap test case in raw_hash_set_allocator_test.

Performance:
- Don't rely on swap so we don't have to do unnecessary copying into the moved-from sets.
- Don't use temp sets in move assignment.
- Default the move constructor of CommonFields.
- Avoid using exchange in raw_hash_set move constructor.
- In `raw_hash_set(raw_hash_set&& that, const allocator_type& a)` with unequal allocators and in move assignment with non-propagating unequal allocators, move set keys instead of copying them.
PiperOrigin-RevId: 570419290
Change-Id: I499e54f17d9cb0b0836601f5c06187d1f269a5b8

1 files changed, 1 insertions, 1 deletions

diff --git a/absl/container/internal/test_allocator.h b/absl/container/internal/test_allocator.h
index adccc214..8e365a3c 100644
--- a/absl/container/internal/test_allocator.h
+++ b/absl/container/internal/test_allocator.h
@@ -364,7 +364,7 @@ void TestSwapAllocPropagation() {
 
     EXPECT_NE(c1.get_allocator(), c2.get_allocator());
     if (IsAssertEnabled()) {
-      EXPECT_DEATH(c2.swap(c1), "");
+      EXPECT_DEATH_IF_SUPPORTED(c2.swap(c1), "");
     }
   }
   EXPECT_EQ(bytes1, 0);