add tests/stdlib/tsugar.nim ; add test case from @mratsim

Author: timotheecour

tests/stdlib/tsugar.nim

@@ -0,0 +1,11 @@
+discard """
+  file: "tsugar.nim"
+  output: ""
+"""
+import sugar
+
+block distinctBase:
+  type
+    Foo[T] = distinct seq[T]
+  var a: Foo[int]
+  doAssert a.type.distinctBase is seq[int]