fix windows build with --free-up-disk

Summary:
getdeps can generate a windows wrapper script that can be used to run build artifacts from build directory.

In github actions for large projects we set a getdeps option delete the build dir as soon as we've successfully installed artefacts to save disk space. This option was enabled for windows in D56165825.   Turns out that didn't work, this diff adds the missing conditional so that it should.

Reviewed By: vitaut

Differential Revision: D56930778

fbshipit-source-id: 0cb9ac94ef9b39f4e33af8fb91098dc0d833731b

build/fbcode_builder/getdeps/builder.py

@@ -158,12 +158,11 @@ def build(self, install_dirs, reconfigure: bool) -> None:
                     os.remove(self.build_dir)
                 else:
                     shutil.rmtree(self.build_dir)
-
-        # On Windows, emit a wrapper script that can be used to run build artifacts
-        # directly from the build directory, without installing them.  On Windows $PATH
-        # needs to be updated to include all of the directories containing the runtime
-        # library dependencies in order to run the binaries.
-        if self.build_opts.is_windows():
+        elif self.build_opts.is_windows():
+            # On Windows, emit a wrapper script that can be used to run build artifacts
+            # directly from the build directory, without installing them.  On Windows $PATH
+            # needs to be updated to include all of the directories containing the runtime
+            # library dependencies in order to run the binaries.
             script_path = self.get_dev_run_script_path()
             dep_munger = create_dyn_dep_munger(self.build_opts, install_dirs)
             dep_dirs = self.get_dev_run_extra_path_dirs(install_dirs, dep_munger)