fixes #2473; cleanup of some tests

tests/vm/tsimpleglobals.nim

@@ -0,0 +1,16 @@
+discard """
+  msg: "abc xyz bb"
+"""
+
+# bug #2473
+type
+  Test = tuple[a,b: string]
+
+static:
+  var s:seq[Test] = @[(a:"a", b:"b")]
+  s[0] = (a:"aa", b:"bb")
+
+  var x: Test
+  x.a = "abc"
+  x.b = "xyz"
+  echo x.a, " ", x.b, " ", s[0].b