Create a blank user config file before running tests

Previously we only removed the properties file but some tests
could touch other parts of the user config so remove it all
and create a blank file to ensure the environment is clean.
Refs #22063

buildconfig/Jenkins/buildscript

@@ -300,10 +300,13 @@ fi
 ###############################################################################
 # Run the unit tests
 ###############################################################################
+# Prevent race conditions when creating the user config directory
+userconfig_dir=$HOME/.mantid
+rm -fr $userconfig_dir
+mkdir -p $userconfig_dir
+touch $userconfig_dir/Mantid.user.properties
+
 if [[ ${DO_UNITTESTS} == true ]]; then
-  # Remove any Mantid.user.properties file
-  userprops=~/.mantid/Mantid.user.properties
-  rm -f $userprops
   $CTEST_EXE -j${BUILD_THREADS:?} --schedule-random --output-on-failure
 fi
 

buildconfig/Jenkins/buildscript.bat

@@ -157,10 +157,14 @@ if ERRORLEVEL 1 exit /B %ERRORLEVEL%
 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
 :: Run the tests
 :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-:: Remove the user properties file just in case anything polluted it
+:: Remove any user configuration and create a blank user properties file
+:: This prevents race conditions when creating the user config directory
 set USERPROPS=bin\%BUILD_CONFIG%\Mantid.user.properties
 del %USERPROPS%
-
+set CONFIGDIR=%APPDATA%\mantidproject\mantid
+rmdir /S /Q %CONFIGDIR%
+mkdir %CONFIGDIR%
+call cmake.exe -E touch %USERPROPS%
 call ctest.exe -C %BUILD_CONFIG% -j%BUILD_THREADS% --schedule-random --output-on-failure
 if ERRORLEVEL 1 exit /B %ERRORLEVEL%