Create default ES_TMPDIR on Windows (#30325)
If the elasticsearch-env bash script chooses $ES_TMPDIR
then it also creates the directory. This change makes
elasticsearch-env.bat do the same thing: if %ES_TMPDIR%
is chosen by the script then the script will ensure it
exists, but if %ES_TMPDIR% is already set then the user
is responsible for creating it.
Relates #27609
Relates #28217