[Math builtins]: Cleanup in ieee754, restoring MSUN version of log2().

test/unittests/base/ieee754-unittest.cc

Index: test/unittests/base/ieee754-unittest.cc
diff --git a/test/unittests/base/ieee754-unittest.cc b/test/unittests/base/ieee754-unittest.cc
index 5f98eff863fe099a116e6dc085599fbd39e10b9c..4a42915099bb3c201100e98129a271053034f041 100644
--- a/test/unittests/base/ieee754-unittest.cc
+++ b/test/unittests/base/ieee754-unittest.cc
@@ -167,6 +167,7 @@ TEST(Ieee754, Log10) {
   EXPECT_EQ(3.7389561269540406, log10(5482.2158));
   EXPECT_EQ(14.661551142893833, log10(458723662312872.125782332587));
   EXPECT_EQ(-0.9083828622192334, log10(0.12348583358871));
+  EXPECT_EQ(5.0, log10(100000.0));
 }
 
 TEST(Ieee754, cbrt) {