randomize number of investments.

[a-t-0]

• Add a random array of uint256 values as argument
• Do not sort it, add another random number as argument for the random number of investments.
• Limit the number of investments to the random number of investments.
• Call the safelyInvest function for the number of investments. Do this by creating a helper function that calls that function for the number of random investments. Returns true/false based on whether all were valid, or a single investment failed. Optionally return the number of valid investments and the number of invalid investments. (Break of the loop early if a single investment fails). Determine exactly what to log.
• Create two test versions, one with the investments all completed before the test, and another with (a random number) of investments being done, followed by the test, followed by a random nr of investments, followed by the test etc.