Refactoring benchmark CI pipeline (shader-slang#4855)

* Refactoring benchmark CI pipeline

* Combine setup and run steps

Author: venkataram-nv

.github/workflows/benchmark.yml

@@ -1,4 +1,4 @@
-name: Benchmark
+name: MDL Benchmark
 
 on:
   push:
@@ -36,12 +36,9 @@ jobs:
         run: |
           cmake --preset default --fresh -DSLANG_SLANG_LLVM_FLAVOR=USE_SYSTEM_LLVM -DCMAKE_COMPILE_WARNING_AS_ERROR=false
           cmake --workflow --preset release
-      - name: Setup
-        run: |
-          cd tests/mdl
-          pip install prettytable argparse
       - name: Run benchmark
         run: |
-          cd tests/mdl
+          cd tools/benchmark
+          pip install prettytable argparse
           Copy-Item -Path C:\slang-benchmarks -Destination . -Recurse
-          python compile.py --samples 16 --target dxil --ci
+          python compile.py --samples 16 --target dxil --ci