Update number of cores used for benchmarking

R=ager@google.com

Bug:
Change-Id: I0618f3dea64d9254b9b310b7db44ffa7c1abd71f

tools/test_framework.py

diff --git a/tools/test_framework.py b/tools/test_framework.py
index 1ade73d..a153847 100755
--- a/tools/test_framework.py
+++ b/tools/test_framework.py
@@ -71,7 +71,7 @@
 
     if args.tool == 'goyt':
       tool_file = GOYT_EXE
-      tool_args = ['--num-threads=4'] + tool_args
+      tool_args = ['--num-threads=8'] + tool_args
     elif args.tool == 'dx':
       tool_file = DX_JAR
     else: