[ICF] Add a NOP after branch in ICF thunk to improve debugability

Author: DataCorrupted

lld/MachO/Arch/ARM64.cpp

@@ -176,6 +176,7 @@ void ARM64::populateThunk(InputSection *thunk, Symbol *funcSym) {
 // Just a single direct branch to the target function.
 static constexpr uint32_t icfSafeThunkCode[] = {
     0x14000000, // 08: b    target
+    0xD503201F, // 0c: nop
 };
 
 void ARM64::initICFSafeThunkBody(InputSection *thunk, Symbol *targetSym) const {