Fix condition in kokoro/test.sh

Logical OR is written as '-o' in bash single-bracket conditions, not '||'.

Change-Id: Id19ec8829dda86cedfc3aeb36e0b992be600100f
diff --git a/kokoro/test.sh b/kokoro/test.sh
index 58cb302..d60d589 100755
--- a/kokoro/test.sh
+++ b/kokoro/test.sh
@@ -101,7 +101,7 @@
     HFTEST_CPU+=(--log "$LOG_DIR_BASE")
   fi
   "${HFTEST_CPU[@]}" arch_test
-  if [ $USE_TFA == true || $USE_FVP == true ]
+  if [ $USE_TFA == true -o $USE_FVP == true ]
   then
     "${HFTEST_CPU[@]}" aarch64_test
   fi