[BE] Add --clean option to install_requirements.py

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.

Test Plan: Tried on my machine

Reviewers:

Subscribers:

Tasks:

Tags:

Author: larryliu0820

install_requirements.py

@@ -78,6 +78,14 @@ def python_is_compatible():
         else:
             print(f"Error: {arg} must follow --pybind")
             sys.exit(1)
+    elif arg == "--clean":
+        print(f"Cleaning build artifacts...")
+        if sys.platform == "win32":
+            subprocess.run(["rmdir", "/s", "cmake-out*/"], check=True)
+            subprocess.run(["rmdir", "/s", "pip-out/"], check=True)
+        else:
+            subprocess.run(["rm", "-rf", "cmake-out*/"], check=True)
+            subprocess.run(["rm", "-rf", "pip-out/"], check=True)
     else:
         print(f"Error: Unknown option {arg}")
         sys.exit(1)