Rollup merge of #136890 - saethlin:swap_nonoverlapping, r=RalfJung

Change swap_nonoverlapping from lang to library UB

The implementation of ptr::swap_nonoverlapping does not always escalate its safety contract to language UB, so it should be `check_library_ub`.

Fixes #4188

tests/fail/ptr_swap_nonoverlapping.rs

@@ -0,0 +1,15 @@
+//! This is a regression test for <https://github.com/rust-lang/miri/issues/4188>: The precondition
+//! check in `ptr::swap_nonoverlapping` was incorrectly disabled in Miri.
+//@normalize-stderr-test: "unsafe \{ libc::abort\(\) \}|crate::intrinsics::abort\(\);" -> "ABORT();"
+//@normalize-stderr-test: "\| +\^+" -> "| ^"
+//@normalize-stderr-test: "\n +[0-9]+:[^\n]+" -> ""
+//@normalize-stderr-test: "\n +at [^\n]+" -> ""
+//@error-in-other-file: aborted execution
+
+fn main() {
+    let mut data = 0usize;
+    let ptr = std::ptr::addr_of_mut!(data);
+    unsafe {
+        std::ptr::swap_nonoverlapping(ptr, ptr, 1);
+    }
+}

tests/fail/ptr_swap_nonoverlapping.stderr

@@ -0,0 +1,31 @@
+
+thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
+unsafe precondition(s) violated: ptr::swap_nonoverlapping requires that both pointer arguments are aligned and non-null and the specified memory ranges do not overlap
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
+thread caused non-unwinding panic. aborting.
+error: abnormal termination: the program aborted execution
+  --> RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
+   |
+LL |     ABORT();
+   | ^ the program aborted execution
+   |
+   = note: BACKTRACE:
+   = note: inside `std::sys::pal::PLATFORM::abort_internal` at RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
+   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `std::sys::backtrace::__rust_end_short_backtrace::<{closure@std::panicking::begin_panic_handler::{closure#0}}, !>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
+   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
+   = note: inside `core::panicking::panic_nounwind` at RUSTLIB/core/src/panicking.rs:LL:CC
+   = note: inside `std::ptr::swap_nonoverlapping::precondition_check` at RUSTLIB/core/src/ub_checks.rs:LL:CC
+   = note: inside `std::ptr::swap_nonoverlapping::<usize>` at RUSTLIB/core/src/ub_checks.rs:LL:CC
+note: inside `main`
+  --> tests/fail/ptr_swap_nonoverlapping.rs:LL:CC
+   |
+LL |         std::ptr::swap_nonoverlapping(ptr, ptr, 1);
+   | ^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+