Richards optCoercion improvement made test cases fail the nice way

This was likely caused by 5e7406d9, which fixed #9233.
Test Trac #9323
Include test case name in performance result

With THREADS=n, for n > 1, it becomes impossible to match the
performance numbers to the test case name. Hence include it in the
output. This also makes grepping through a bunch of logs for a specific
test case much easier, and outweighs the extra verbosity.
Adjust a few performance numbers

These did not yet trigger a failure, but are more than 1% away from the
expected value. Since I now start collecting logs to investigate
deviations from the expected value, it makes sense to reset them. This
way we know that every significat deviation was caused since this
commit.

I only updated bytes_allocated numbers, as these are (mostly)
deterministic. Other depend, AFAIK, on sampling timing, so I did not
bother.
Correctly round when calculating the deviation
Try travis again with CPUS=2

(This setting used to work with ghc-complete...)