Fix IIS benchmark regression

[pakrym]

It is passing published\Benchmarks.dll to w3wp.exe:

[12:47:17.307] Generating application host config for 'C:\Users\Administrator\AppData\Local\Temp\BenchmarksServer\x242h3sv.c2s\dotnet.exe  --nonInteractive true --scenarios PlaintextNonPipelined --server IISInProcess'
[12:47:17.308] Invoking executable: C:\Windows\System32\inetsrv\w3wp.exe, with arguments: published\Benchmarks.dll  -h "C:\Users\Administrator\AppData\Local\Temp\BenchmarksServer\x242h3sv.c2s\dotnet.exe.apphost.config"

#497

[pakrym]

Tested, works locally.