Remove clobbers_all_regs

cranelift/codegen/meta/src/gen_inst.rs

@@ -524,13 +524,6 @@ fn gen_opcodes(all_inst: &AllInstructions, fmt: &mut Formatter) {
             "Does this instruction write to CPU flags?",
             fmt,
         );
-        gen_bool_accessor(
-            all_inst,
-            |inst| inst.clobbers_all_regs,
-            "clobbers_all_regs",
-            "Should this opcode be considered to clobber all the registers, during regalloc?",
-            fmt,
-        );
     });
     fmt.line("}");
     fmt.empty_line();