Add missing virtual destructors to tests.

Change-Id: I916b1e646d9fe142d3483039eb6cc72464529832

test/borders_test.cc

@@ -21,6 +21,7 @@ class BordersTest : public ::libvpx_test::EncoderTest,
     public ::libvpx_test::CodecTestWithParam<libvpx_test::TestMode> {
  protected:
   BordersTest() : EncoderTest(GET_PARAM(0)) {}
+  virtual ~BordersTest() {}
 
   virtual void SetUp() {
     InitializeConfig();

test/config_test.cc

@@ -20,6 +20,7 @@ class ConfigTest : public ::libvpx_test::EncoderTest,
  protected:
   ConfigTest() : EncoderTest(GET_PARAM(0)),
                  frame_count_in_(0), frame_count_out_(0), frame_count_max_(0) {}
+  virtual ~ConfigTest() {}
 
   virtual void SetUp() {
     InitializeConfig();

test/cpu_speed_test.cc

@@ -22,6 +22,7 @@ class CpuSpeedTest : public ::libvpx_test::EncoderTest,
         libvpx_test::TestMode, int> {
  protected:
   CpuSpeedTest() : EncoderTest(GET_PARAM(0)) {}
+  virtual ~CpuSpeedTest() {}
 
   virtual void SetUp() {
     InitializeConfig();

test/keyframe_test.cc

@@ -21,6 +21,7 @@ class KeyframeTest : public ::libvpx_test::EncoderTest,
     public ::libvpx_test::CodecTestWithParam<libvpx_test::TestMode> {
  protected:
   KeyframeTest() : EncoderTest(GET_PARAM(0)) {}
+  virtual ~KeyframeTest() {}
 
   virtual void SetUp() {
     InitializeConfig();

test/superframe_test.cc

@@ -21,6 +21,7 @@ class SuperframeTest : public ::libvpx_test::EncoderTest,
  protected:
   SuperframeTest() : EncoderTest(GET_PARAM(0)), modified_buf_(NULL),
       last_sf_pts_(0) {}
+  virtual ~SuperframeTest() {}
 
   virtual void SetUp() {
     InitializeConfig();