make tests green again

tests/exprs/tstmtexprs.nim

@@ -33,7 +33,7 @@ when true:
     if (var yy = 0; yy != 0):
       echo yy
     else:
-      echo(try: parseInt("1244") except EINvalidValue: -1)
+      echo(try: parseInt("1244") except ValueError: -1)
     result = case x
              of 23: 3
              of 64:
@@ -87,7 +87,7 @@ proc parseResponse(): JsonNode =
     var excMsg = key & "("
     if (var n=result["key2"]; n != nil):
       excMsg &= n.str
-    raise newException(ESynch, excMsg)
+    raise newException(SystemError, excMsg)
 
 
 
@@ -99,7 +99,7 @@ let b = (se[1] = 1; 1)
 # bug #1161
 
 type
-  PFooBase = ref object of PObject
+  PFooBase = ref object of RootRef
     field: int
 
   PFoo[T] = ref object of PFooBase