Fix constructor order in unit tests (sanitizer)

The WithParamTest constructor needs to be called first, as the
EncoderTest constructor is called with 'GET_PARAM'.

BUG=aomedia:580

Change-Id: I17f3c02c0a0eec103fb3505301b5eb6dfdef851c
diff --git a/test/encode_perf_test.cc b/test/encode_perf_test.cc
index e2a4f2b..8125e6b 100644
--- a/test/encode_perf_test.cc
+++ b/test/encode_perf_test.cc
@@ -56,8 +56,8 @@
 #define NELEMENTS(x) (sizeof((x)) / sizeof((x)[0]))
 
 class AV1EncodePerfTest
-    : public ::libaom_test::EncoderTest,
-      public ::libaom_test::CodecTestWithParam<libaom_test::TestMode> {
+    : public ::libaom_test::CodecTestWithParam<libaom_test::TestMode>,
+      public ::libaom_test::EncoderTest {
  protected:
   AV1EncodePerfTest()
       : EncoderTest(GET_PARAM(0)), min_psnr_(kMaxPsnr), nframes_(0),