Add --clean option to install_requirements.py (#5348)

Summary:
as titled. remove `cmake-out/` and `pip-out/` before installing ExecuTorch. Android is creating directory name such as `cmake-out-armv8` so removing those as well.

Pull Request resolved: #5348

Test Plan:
Tried on my machine

```
$ bash install_requirements.sh --clean
Cleaning build artifacts...
Cleaning pip-out/...
Cleaning cmake-out-android-arm64-v8a/...
Cleaning cmake-out-android-x86_64/...
Done cleaning build artifacts.
```

Reviewed By: kimishpatel, dbort

Differential Revision: D62648278

Pulled By: larryliu0820

fbshipit-source-id: 3699015fe4b960d8087556cb29388863df10285b

Author: larryliu0820

install_requirements.py

@@ -5,9 +5,11 @@
 # LICENSE file in the root directory of this source tree.
 
 
+import glob
 import os
 import platform
 import re
+import shutil
 import subprocess
 import sys
 
@@ -78,6 +80,16 @@ def python_is_compatible():
         else:
             print(f"Error: {arg} must follow --pybind")
             sys.exit(1)
+    elif arg == "--clean":
+        print("Cleaning build artifacts...")
+        print("Cleaning pip-out/...")
+        shutil.rmtree("pip-out/", ignore_errors=True)
+        dirs = glob.glob("cmake-out*/")
+        for d in dirs:
+            print(f"Cleaning {d}...")
+            shutil.rmtree(d, ignore_errors=True)
+        print("Done cleaning build artifacts.")
+        sys.exit(0)
     else:
         print(f"Error: Unknown option {arg}")
         sys.exit(1)