Construct logFileName in a way that works even if __FILE__ marco star…

…ts with "./" as is the case for LLVM flang-new.

src/epilogue/src/ESMF_Test.F90

@@ -799,11 +799,10 @@ subroutine ESMF_TestStart(file, line, unit, rc)
       ! create a file name for the log file
       ! find locations of the underscore and period
       underScore = index (file, "_")
-      Period = index (file, ".")
+      Period = index (file, substring=".", back=.true.) ! search from back of string,
+                                                        ! safe for ./file start
       logFileName = file(underScore+1:Period)  // "Log"
 
-
-
       ! initialize the framework.  if this fails, print a message directly
       ! because there is no guarentee that the log code will be working.
       call ESMF_Initialize(vm=globalVM, defaultlogfilename=logFileName, &