Add comprehensive unit tests for TicTacToe and NestedArray contracts

[pali101]

This PR introduces improved unit tests for the TicTacToe and NestedArray contracts:

• TicTacToe Contract Tests

  • Tests for winning conditions in rows, columns, and diagonals for both 1s and 0s.
  • Tests with all 1s and all 0s to confirm both are treated as wins.
  • Mixed configurations with no winning lines to ensure correct detection of non-winning states.
  • Added cases with incomplete rows/columns and mixed values that should return false for isWinning.

• NestedArray Contract Tests:

  • Includes tests for handling large numbers and nested structures.
  • Arrays with maximum and minimum values, including empty and fully populated arrays.