fix some trivial errors in the test suite and some more regressions caused by tyTypeDesc[tyNone]

tests/global/globalaux.nim

@@ -0,0 +1,15 @@
+type 
+  TObj*[T] = object
+    val*: T
+
+var
+  totalGlobals* = 0
+
+proc makeObj[T](x: T): TObj[T] =
+  totalGlobals += 1
+  result.val = x
+
+proc globalInstance*[T]: var TObj[T] =
+  var g {.global.} = when T is int: makeObj(10) else: makeObj("hello")
+  result = g
+