refactor(cmd): consolidate cross-arch verify and drop dead code

cmd/gasm/debug_linux.go

@@ -84,7 +84,7 @@ REPL commands:
 	if *timeout > 0 {
 		go func() {
 			time.Sleep(*timeout)
-			fmt.Fprintf(os.Stderr, "gasm debug: timeout (%s) — killing the debuggee\n", *timeout)
+			fmt.Fprintf(os.Stderr, "gasm debug: timeout (%s), killing the debuggee\n", *timeout)
 			os.Exit(3)
 		}()
 	}
@@ -140,7 +140,6 @@ REPL commands:
 		}
 
 		// Construct the argument block with buffer pointers at the correct positions.
-		bufIdx := 0
 		for _, arg := range layout {
 			if !arg.IsPtr {
 				continue
@@ -170,12 +169,10 @@ REPL commands:
 							argBlock[off+16+j] = byte(size >> (j * 8))
 						}
 					}
-					bufIdx++
 					break
 				}
 			}
 		}
-		_ = bufIdx
 	} else {
 		argBlock = make([]byte, fl.Args)
 		sess, err = debug.Launch("", path, *funcName, argBlock)