Rename test class "Daala" to "DivuSmallTest".

The test file name is divu_small_test.cc. (It tests the OD_DIVU_SMALL
macro.) By convention the test class in the file should be named
DivuSmallTest.

Tested:
test_libaom --gtest_filter=DivuSmallTest.*

BUG=aomedia:2616

Change-Id: I80c75b2dac578a89072a6545e4c0eb0a08bbd279
diff --git a/test/divu_small_test.cc b/test/divu_small_test.cc
index 064f8ee..f4d0846 100644
--- a/test/divu_small_test.cc
+++ b/test/divu_small_test.cc
@@ -18,7 +18,7 @@
 
 using libaom_test::ACMRandom;
 
-TEST(Daala, TestDIVUuptoMAX) {
+TEST(DivuSmallTest, TestDIVUuptoMAX) {
   for (int d = 1; d <= OD_DIVU_DMAX; d++) {
     for (uint32_t x = 1; x <= 1000000; x++) {
       GTEST_ASSERT_EQ(x / d, OD_DIVU_SMALL(x, d))
@@ -28,7 +28,7 @@
   }
 }
 
-TEST(Daala, TestDIVUrandI31) {
+TEST(DivuSmallTest, TestDIVUrandI31) {
   ACMRandom rnd(ACMRandom::DeterministicSeed());
   for (int d = 1; d < OD_DIVU_DMAX; d++) {
     for (int i = 0; i < 1000000; i++) {