Restore the Nim's 0.14 proper handling of generic aliases

A more efficient implementation is possible by restoring the old
lifting ot tyGenericInvocation to tyGenericInst in liftTypeParam,
but this fix will suffice for now.

fixes #5087
fixes #5602
fixes #5641
fixes #5570

tests/generics/t5570.nim

@@ -0,0 +1,27 @@
+discard """
+  nimout: "type uint32\ntype uint32"
+  output: "(weight: 17.0, color: 100)"
+"""
+
+import macros
+
+type
+  BaseFruit[T] = object of RootObj
+    color: T
+
+  Banana[T] = object of BaseFruit[uint32]
+    weight: T
+
+macro printTypeName(typ: typed): untyped =
+  echo "type ", getType(typ).repr
+
+proc setColor[K](self: var BaseFruit[K], c: int) =
+  printTypeName(self.color)
+  self.color = uint32(c)
+
+var x: Banana[float64]
+x.weight = 17
+printTypeName(x.color)
+x.setColor(100)
+echo x
+