Revert " backends.py: add simulation to CBMC backend"

This reverts commit 6df61b2.

Author: lou1306

backends.py

@@ -294,32 +294,6 @@ def get_cmdline(self, fname, _):
         cmd.append(fname)
         return cmd
 
-    def simulate(self, fname, info):
-        exe = os.environ.get("CBMC") or (
-            str(self.cwd / "backends" / "cbmc-5.42.0" / "bin" / "cbmc")
-            if "Linux" in platform.system()
-            else "cbmc")
-        glucose = str(self.cwd / "backends" / "glucose" / "glucose-nondet.sh")
-        cmd = [
-            exe,
-            "--external-sat-solver", glucose,
-            "--trace",
-            "--stop-on-fail"
-        ]
-        cmd.append(fname)
-        log_call(cmd)
-        try:
-            out = check_output(cmd, stderr=STDOUT, cwd=self.cwd).decode()
-            self.verbose_output(out, "Backend output")
-        except CalledProcessError as err:
-            out = err.output.decode("utf-8")
-            self.verbose_output(out, "Backend output")
-            try:
-                print(*translateCPROVER(out, fname, info), sep="", end="")
-            except Exception as e:
-                print(f"Counterexample translation failed: {e}")
-        return ExitStatus.SUCCESS
-
     def check_cli(self):
         super().check_cli()
         if not self.cli[Args.STEPS] and not self.cli[Args.SHOW]: