Using ::testing::DoAll

Without this statement, compilation failed with new googletest.

Exempt-From-Owner-Approval: Fix unit test.
Test: build
Bug: 129498355
Change-Id: I522ef9614439ba1630e29788f7512180feea01de
diff --git a/tests/os_unittest.cpp b/tests/os_unittest.cpp
index 0cfb493..a014973 100644
--- a/tests/os_unittest.cpp
+++ b/tests/os_unittest.cpp
@@ -38,8 +38,9 @@
 namespace {
 
 using ::testing::_;
-using ::testing::Invoke;
+using ::testing::DoAll;
 using ::testing::InSequence;
+using ::testing::Invoke;
 using ::testing::Matcher;
 using ::testing::MatcherInterface;
 using ::testing::MatchResultListener;
@@ -48,8 +49,8 @@
 using ::testing::Return;
 using ::testing::SetArgumentPointee;
 using ::testing::SetErrnoAndReturn;
-using ::testing::StrictMock;
 using ::testing::StrEq;
+using ::testing::StrictMock;
 
 using local_utils::GetMaxVal;