keep only the relevant part of tbasics test

tests/js/tbasics.nim

@@ -1,42 +1,7 @@
 discard """
-  output: '''ABCDC
-1
-14
-ok
-1'''
+  output: '''1'''
 """
 
-type
-  MyEnum = enum
-    A,B,C,D
-# trick the optimizer with an seq:
-var x = @[A,B,C,D]
-echo x[0],x[1],x[2],x[3],MyEnum(2)
-
-# bug #10651
-
-var xa: seq[int]
-var ya = @[1,2]
-xa &= ya
-echo xa[0]
-
-proc test =
-  var yup: seq[int]
-  try:
-    yup.add 14
-    echo yup.pop
-  finally:
-    discard
-
-test()
-
-when true:
-  var a: seq[int]
-
-  a.setLen(0)
-
-  echo "ok"
-
 # bug #10697
 proc test2 =
   var val = uint16(0)