Remove FIXME in tests/compile-fail/panic/bad_unwind.rs

Author: hyd-dev

tests/compile-fail/panic/bad_unwind.rs

@@ -4,8 +4,6 @@
 //! Unwinding when the caller ABI is "C" (without "-unwind") is UB.
 //! Currently we detect the ABI mismatch; we could probably allow such calls in principle one day
 //! but then we have to detect the unexpected unwinding.
-//! FIXME: `-Zmiri-disable-abi-check` does not work for this test because function pointers are
-//! always allowed to unwind.
 
 extern "C-unwind" fn unwind() {
     panic!();