Comment dummy memory allocation for AllocKind::{Function, VTable}

Co-authored-by: Ralf Jung <post@ralfj.de>

Author: Strophox

src/tools/miri/src/alloc_addresses/mod.rs

@@ -191,6 +191,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                             }
                         }
                         AllocKind::Function | AllocKind::VTable => {
+                            // Allocate some dummy memory to get a unique address for this function/vtable.
                             let alloc_bytes = MiriAllocBytes::from_bytes(&[0u8; 1], Align::from_bytes(1).unwrap());
                             let addr = alloc_bytes.as_ptr().addr().try_into().unwrap();
                             // Leak this.