bazel run do not clean/regenerate runfiles

### Description of the problem / feature request:

When a binary run by `bazel run` generates files in its working directory (i.e. its `runfiles`), they stay for the next run.

I would like them to be cleaned at each `bazel run` invocation. Right now I need to `bazel clean` before. A flag, such as `bazel run --clean_runfiles` is another option.

### Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

If target `//:foo` looks like this pseudo code:

```shell
if fileExists "a"
then echo "Exists"
else echo "Does not exist"

createFile "a"
```

The following:

```bazel clean; bazel run //:foo; bazel run //:foo` will print "Do not exists" followed by "Exists".

### What operating system are you running Bazel on?

Linux

### What's the output of `bazel info release`?

```release 4.1.0- (@non-git)```

### If `bazel info release` returns "development version" or "(@non-git)", tell us how you built Bazel.

NixOS

### Have you found anything relevant by searching the web?

### Any other information, logs, or outputs that you want to share?

Start at the bazel run entry point and reproduce the issue with the supplied //:foo sequence on Linux. Determine how runfiles are prepared between invocations; done means generated files are cleaned or regenerated on each run, or an explicitly documented cleaning option provides that behavior.

Written by the indexing model from the issue text.