Fix conflicts after rebase

- r-l/r 126784
- r-l/r 127113
- r-l/miri 3562

Author: WaffleLapkin

tests/fail/tail_calls/cc-mismatch.stderr

@@ -8,7 +8,7 @@ LL |     extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE:
    = note: inside `<fn() as std::ops::FnOnce<()>>::call_once - shim(fn())` at RUSTLIB/core/src/ops/function.rs:LL:CC
-   = note: inside `std::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>` at RUSTLIB/std/src/sys_common/backtrace.rs:LL:CC
+   = note: inside `std::sys::backtrace::__rust_begin_short_backtrace::<fn(), ()>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
    = note: inside closure at RUSTLIB/std/src/rt.rs:LL:CC
    = note: inside `std::ops::function::impls::<impl std::ops::FnOnce<()> for &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>::call_once` at RUSTLIB/core/src/ops/function.rs:LL:CC
    = note: inside `std::panicking::r#try::do_call::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at RUSTLIB/std/src/panicking.rs:LL:CC

tests/fail/tail_calls/signature-mismatch-arg.stderr

@@ -7,7 +7,7 @@ LL |     f(0);
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = help: this means these two types are not *guaranteed* to be ABI-compatible across all targets
-   = help: if you think this code should be accepted anyway, please report an issue
+   = help: if you think this code should be accepted anyway, please report an issue with Miri
    = note: BACKTRACE:
    = note: inside `main` at $DIR/signature-mismatch-arg.rs:LL:CC