run-tests: allow different extra weight for slow tests
The 'test-check-code-hg.t' file is not big enough to be prioritized properly.
As a result my tests run often spend about 15 seconds running only it at the
end of its tests run. We make the "slow" mechanism a bit smarter to adjust the
extra weight of each category independently in a future patch.
$ hg init
$ echo a > a
$ hg ci -Am t
adding a
$ hg mv a b
$ hg ci -Am t1
$ hg debugrename b
b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
$ hg mv b a
$ hg ci -Am t2
$ hg debugrename a
a renamed from b:37d9b5d994eab34eda9c16b195ace52c7b129980
$ hg debugrename --rev 1 b
b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3