Mock time for our timer tests
Mock time for our timer tests

This change updates the s2n timer tests to use a mocked out wall clock
time. This should avoid false negative unit test failures due to
inaccurate system clocks and slow test servers.

PKRoma/s2n,bpdavidson/s2n,bpdavidson/s2n,wcs1only/s2n,jldodds/s2n,bpdavidson/s2n,raycoll/s2n,colmmacc/s2n,wcs1only/s2n,jldodds/s2n,jldodds/s2n,PKRoma/s2n,bpdavidson/s2n,jldodds/s2n,colmmacc/s2n,wcs1only/s2n,raycoll/s2n,bpdavidson/s2n,gibson-compsci/s2n,awslabs/s2n,colmmacc/s2n,wcs1only/s2n,awslabs/s2n,alexeblee/s2n,raycoll/s2n,PKRoma/s2n,gibson-compsci/s2n,colmmacc/s2n,alexeblee/s2n,PKRoma/s2n,colmmacc/s2n,raycoll/s2n,raycoll/s2n,raycoll/s2n,bpdavidson/s2n,PKRoma/s2n,PKRoma/s2n,wcs1only/s2n,gibson-compsci/s2n,PKRoma/s2n,awslabs/s2n,alexeblee/s2n,awslabs/s2n,colmmacc/s2n,gibson-compsci/s2n,alexeblee/s2n,alexeblee/s2n,wcs1only/s2n,alexeblee/s2n,awslabs/s2n,PKRoma/s2n,gibson-compsci/s2n,wcs1only/s2n,gibson-compsci/s2n,jldodds/s2n,wcs1only/s2n,awslabs/s2n