Endless option does not have endless tests

[YunSuk]

Currently, Endless option under Length of test is same as 6 tests option.
Endless should result in endless number of tests.

75 points

[chuchengLin]

Working on it

[YunSuk]

It is not truly endless, but practically endless. They used int max to make the test length endless.

It is practically impossible to achieve true endless since the app is also calculating the percentage gotten correctly, which requires number of tests taken so far.

One can try to use infinite loop and use BigInteger to store number of tests, but that is not truly endless either due to limitation of phone's memory.

So, I believe this solution is reasonable, but one can still implement the suggestion above for 50 points.

[seemantasaha]

W18 OK. 50 points. I may close it later based on the requirement to fix it.