Comparing collection using equals method for assertEquals

[prashant-maroti]

Fixes #2296
To check whether the two objects are equal, have replaced all the comparison operator (=) with equals method for non primitive data types. This will add capability to compare the sets as they do not always guarantee the insertion order.

[juherr]

Please check everywhere actual == expected is used.
Especially https://github.com/cbeust/testng/blame/master/src/main/java/org/testng/Assert.java#L1352

[prashant-maroti]

@juherr @krmahadevan Have replaced all the occurrences of comparison operator (=) with 'equals' method for non primitive data types.

[prashant-maroti]

@krmahadevan Kindly review. Have resolved the conflicts with master.