Remove unused package in primary benchmark script (shader-slang#5014)

Also fixes the self-hosted machine that is used for benchmarking, so that variance of timings can be reduced.

Author: venkataram-nv

.github/workflows/push-benchmark-results.yml

@@ -14,7 +14,7 @@ concurrency:
 
 jobs:
   build:
-    runs-on: [Windows, self-hosted]
+    runs-on: [Windows, benchmark, self-hosted]
     steps:
       - uses: actions/checkout@v3
         with:

tools/benchmark/compile.py

@@ -3,7 +3,6 @@
 import glob
 import subprocess
 import argparse
-import halo
 import sys
 import prettytable
 import json