Store bisection logs in test directory

Store bisection search logs in test directory for easier access.

Test: ./test/run-test --never-clean --no-prebuild --bisection-search
037-inherit
Change-Id: I67e472b933516f0e486f47fd2c7a4ae06212db44
diff --git a/test/run-test b/test/run-test
index c50a9ca..7a4afaf 100755
--- a/test/run-test
+++ b/test/run-test
@@ -937,6 +937,7 @@
         --raw-cmd="$raw_cmd" \
         --check-script="$cwd/check" \
         --expected-output="$cwd/expected.txt" \
+        --logfile="$cwd/bisection_log.txt" \
         --timeout=300
     fi
 fi