Remove the not-a-term argument which is not supported in older Vim versions and NeoVim

test/run_mru_tests.sh

@@ -3,7 +3,7 @@
 # Script to run the unit-tests for the MRU Vim plugin
 
 VIMPRG=${VIMPRG:=/usr/bin/vim}
-VIM_CMD="$VIMPRG -N -u NONE -U NONE -i NONE --not-a-term"
+VIM_CMD="$VIMPRG -N -u NONE -U NONE -i NONE"
 
 $VIM_CMD -S unit_tests.vim