[Tests] try to make `nvm unload` test more robust

test/fast/Running "nvm unload" should unset all function and variables.

@@ -5,11 +5,11 @@ set -ex
 BEFORE="./before.tmp"
 AFTER="./after.tmp"
 
-cleanup () { rm -f "${BEFORE}" "${AFTER}"; }
+cleanup () { echo rm -f "${BEFORE}" "${AFTER}"; }
 die () { echo "$@" ; cleanup ; exit 1; }
 
 typeset -f | awk '/ \(\) $/ && !/^main / {print $1}' > "${BEFORE}"
-env | grep -v PATH= | grep -v NVM_ >> "${BEFORE}"
+env | grep -v PATH= | grep -v IFS= | grep -v NVM_ | sort >> "${BEFORE}"
 
 set +e # TODO: fix
 \. ../../nvm.sh
@@ -20,7 +20,7 @@ type nvm > /dev/null 2>&1 || die "nvm not loaded"
 nvm unload
 
 typeset -f | awk '/ \(\) $/ && !/^main / {print $1}' > "${AFTER}"
-env | grep -v PATH= >> "${AFTER}"
+env | grep -v PATH= | grep -v IFS= | sort >> "${AFTER}"
 
 ! type nvm > /dev/null 2>&1 || die "nvm not unloaded"