Fix a bunch of missing unwinder related definitions

cg_llvm likely just optimizes out their references for these tests, but
cg_clif doesn't and would thus give a linker error.

tests/ui/allocator/no_std-alloc-error-handler-custom.rs

@@ -6,13 +6,14 @@
 //@ compile-flags:-C panic=abort
 //@ aux-build:helper.rs
 
-#![feature(rustc_private, lang_items)]
+#![feature(rustc_private, lang_items, panic_unwind)]
 #![feature(alloc_error_handler)]
 #![no_std]
 #![no_main]
 
 extern crate alloc;
 extern crate libc;
+extern crate unwind; // For _Unwind_Resume
 
 // ARM targets need these symbols
 #[no_mangle]

tests/ui/allocator/no_std-alloc-error-handler-default.rs

@@ -6,12 +6,13 @@
 //@ compile-flags:-C panic=abort
 //@ aux-build:helper.rs
 
-#![feature(rustc_private, lang_items)]
+#![feature(rustc_private, lang_items, panic_unwind)]
 #![no_std]
 #![no_main]
 
 extern crate alloc;
 extern crate libc;
+extern crate unwind; // For _Unwind_Resume
 
 // ARM targets need these symbols
 #[no_mangle]

tests/ui/no_std/simple-runs.rs

@@ -4,6 +4,7 @@
 //@ compile-flags: -Cpanic=abort
 //@ ignore-wasm different `main` convention
 
+#![feature(lang_items)]
 #![no_std]
 #![no_main]
 
@@ -35,6 +36,17 @@ fn panic_handler(_info: &PanicInfo<'_>) -> ! {
     loop {}
 }
 
+#[lang = "eh_personality"]
+extern "C" fn rust_eh_personality(
+    _version: i32,
+    _actions: i32,
+    _exception_class: u64,
+    _exception_object: *mut (),
+    _context: *mut (),
+) -> i32 {
+    loop {}
+}
+
 #[no_mangle]
 extern "C" fn main(_argc: c_int, _argv: *const *const c_char) -> c_int {
     0