FindMatlab: add'l check that Matlab test version file exists

this last resort check is for some HPC with "module load matlab"
not enacted that fail to catch in earlier checks. That would
error CMake configure even if find_package(Matlab) is not REQUIRED

Modules/FindMatlab.cmake

@@ -843,6 +843,15 @@ function(matlab_get_version_from_matlab_run matlab_binary_program matlab_list_ve
     endif()
   endif()
 
+  if(NOT EXISTS "${_matlab_temporary_folder}/matlabVersionLog.cmaketmp")
+    # last resort check as some HPC with "module load matlab" not enacted fail to catch in earlier checks
+    # and error CMake configure even if find_package(Matlab) is not REQUIRED
+    if(MATLAB_FIND_DEBUG)
+      message(WARNING "[MATLAB] Unable to determine the version of Matlab. The version log file does not exist.")
+    endif()
+    return()
+  endif()
+
   # if successful, read back the log
   file(READ "${_matlab_temporary_folder}/matlabVersionLog.cmaketmp" _matlab_version_from_cmd)
   file(REMOVE "${_matlab_temporary_folder}/matlabVersionLog.cmaketmp")