new db_sqlite requires deadCodeElim:on because not every sqlite3_column_name

lib/impure/db_sqlite.nim

@@ -40,6 +40,8 @@
 ##
 ##  theDb.close()
 
+{.deadCodeElim:on.}
+
 import strutils, sqlite3
 
 import db_common

tests/closure/tissue1642.nim

@@ -1,7 +0,0 @@
-discard """
-  file: "tissue1642.nim"
-  disabled: true
-"""
-block:
-  var i = 0
-  proc p() = inc(i)