So you can do and get:
```
▶ ./benchSite.sh "YAML,num_pages=10"
Running with BenchmarkSiteBuilding/YAML,num_pages=10
BenchmarkSiteBuilding/YAML,num_pages=10-4 1000 1611261 ns/op 730749 B/op 6458 allocs/op
PASS
ok github.com/spf13/hugo/hugolib 8.168s
```
And change site benchmark separator to comma to make it Bash and regexp friendly, example:
./benchSite.sh "frontmatter=YAML,num_root_sections=1,num_pages=.*,tags_per_page=20,shortcodes=false,render=false"
To run a subset of these benchmark, one can do something like this:
```
go test -run="NONE" -bench="BenchmarkSiteBuilding/tags_per_page=0.*shortcodes=true.*render=false" -test.benchmem=true ./hugolib
```
Which will run without any tags, with shortcodes, but will skip rendering.
Fixes#3535
