fixes #5871

tests/exception/tfinally3.nim

@@ -1,6 +1,11 @@
 discard """
   file: "tfinally3.nim"
-  output: "false"
+  output: '''false
+Within finally->try
+Traceback (most recent call last)
+tfinally3.nim(24)        tfinally3
+Error: unhandled exception: First [Exception]'''
+  exitCode: 1
 """
 # Test break in try statement:
 
@@ -14,5 +19,11 @@ proc main: bool =
 
 echo main() #OUT false
 
-
-
+# bug #5871
+try:
+  raise newException(Exception, "First")
+finally:
+  try:
+    raise newException(Exception, "Within finally->try")
+  except:
+    echo getCurrentExceptionMsg()