This commit fixes adding the tools directory to the user's PATH for the native
installers.
The issue was a regression caused by #8886. The change used a "no-op" sentinel
file that reported it existed. This "no-op" sentinel was used for the native
installers. Unlike the other "no-op" sentinels used by the native installer,
we do want PATH to be modified by the native installer.
The fix is to change the "no-op" sentinel to report the file doesn't exist, but
also to not to attempt to create the file.
This fixes#9208.