Add -g to art script --perf-report

Gives a basic call stack, good for knowing what calls what.

Test: art --perf-report

Change-Id: Ifa44040491ed865bf839d62622494d951f2bcd62
diff --git a/tools/art b/tools/art
index d91b451..1a3bba7 100644
--- a/tools/art
+++ b/tools/art
@@ -87,7 +87,7 @@
 fi
 
 if [ z"$PERF" != z ]; then
-  invoke_with="perf record -o $ANDROID_DATA/perf.data -e cycles:u $invoke_with"
+  invoke_with="perf record -g -o $ANDROID_DATA/perf.data -e cycles:u $invoke_with"
   DEBUG_OPTION="-Xcompiler-option --generate-debug-info"
 fi