fix issue with exploiting parallelism

Author: tr4n2uil

config/suite.testng.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
-<suite name="Pool" thread-count="4" parallel="classes">
-    <test name="PoolTestChrome">
+<suite name="Pool" parallel="tests">
+    <test name="PoolTestChrome" thread-count="3" parallel="classes">
         <parameter name="config" value="suite.conf.json"/>
         <parameter name="environment" value="chrome"/>
         <classes>
@@ -18,7 +18,7 @@
         </classes>
     </test>
 
-    <test name="PoolTestFirefox">
+    <test name="PoolTestFirefox" thread-count="3" parallel="classes">
         <parameter name="config" value="suite.conf.json"/>
         <parameter name="environment" value="firefox"/>
         <classes>