Increase Haskell log file resolution

Currently the Haskell logging goes with the default time formatting,
which lacks sub-second resolution. This is not good, as it's too
coarse.

The patch adds picoseconds to the log; they will contain usually too
many zeroes, but the other option is to use a log format that (for
precisely zero fractional part) omits the separator, so it's not
consistent from line to line, and which also uses a dot as a
separator, different from the Python code.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>