fix timestamp test

The existing timestamp test checked the values within 50ms of each
other, since 50ms was a realistic latency for the existing test
framework (locally on travis with pg, mysql, etc). The mssql tests
generally take much longer, but this solution accounts for both and
future cases.

test/timezone.test.js

@@ -22,7 +22,7 @@ if (dialect !== 'sqlite') {
       var now = 'now()'
         , startQueryTime = Date.now();
 
-      if(dialect === 'mssql'){
+      if (dialect === 'mssql') {
         now = 'GETDATE()';
       }