Merge branch 'jk/t5551-expensive-test-timeouts-fix'

The Apache timeout in HTTP tests has been increased to prevent test failures on heavily loaded CI runners. The tests creating an enormous number of refs have been isolated to their own repositories to avoid slowing down subsequent tests. * jk/t5551-expensive-test-timeouts-fix: t5551: put many-tags case into its own repo t/lib-httpd: bump apache timeout