Add build flag for iterative vm testing.

bin/cros_run_vm_test

Index: bin/cros_run_vm_test
diff --git a/bin/cros_run_vm_test b/bin/cros_run_vm_test
index 8c7f68f97323cb313ff7db290fa87f03f13a52b0..1b0e6d9be917739eaee5f5dd721b57b963557279 100755
--- a/bin/cros_run_vm_test
+++ b/bin/cros_run_vm_test
@@ -36,7 +36,8 @@ MAX_RETRIES=3
 get_default_board
 
 DEFINE_string board "$DEFAULT_BOARD" \
-    "The board for which you built autotest." b
+    "The board for which you built autotest."
+DEFINE_boolean build ${FLAGS_FALSE} "Build tets while running" b
 DEFINE_string image_path "" "Full path of the VM image"
 DEFINE_string results_dir_root "" "alternate root results directory"
 DEFINE_string test_case "" "Name of the test case to run"
@@ -104,8 +105,13 @@ if [ -n "${FLAGS_verify_chrome_version}" ]; then
   fi
 fi
 
+# Set the build flag for run_remote_tests.
+BUILD_FLAG=""
+[ ${FLAGS_build}-eq ${FLAGS_true} ] && BUILD_FLAG="--build"
+
 "${SCRIPTS_DIR}/run_remote_tests.sh" \
     --board=${FLAGS_board} \
+    ${BUILD_FLAG} \
     --ssh_port=${FLAGS_ssh_port} \
     --remote=127.0.0.1 \
     --results_dir_root="${FLAGS_results_dir_root}" \