message: Use existing tcx instead
diff: @@ -127,7 +127,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  let tcx = &{ this.tcx.tcx };
  let buf = this.force_ptr(this.read_scalar(buf_op)?.not_undef()?)?;
  - let size = this.read_scalar(size_op)?.to_usize(&*this.tcx)?;
  + let size = this.read_scalar(size_op)?.to_usize(&*tcx)?;
  // If we cannot get the current directory, we return null
  match env::current_dir() {
  Ok(cwd) => {
  @@ -152,7 +152,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  }
  Err(e) => this.consume_io_error(e)?,
  }
  - Ok(Scalar::ptr_null(&*this.tcx))
  + Ok(Scalar::ptr_null(&*tcx))
  }
  fn chdir(&mut self, path_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
  