Make sure double to int conversion is correct.

test/cctest/test-utils.cc

Index: test/cctest/test-utils.cc
diff --git a/test/cctest/test-utils.cc b/test/cctest/test-utils.cc
index df8ff72e4f3eafed1e85aad150b2ce0d0a93f409..2ff4e6f440117aec2400aec6fb4ce52c80fc5af5 100644
--- a/test/cctest/test-utils.cc
+++ b/test/cctest/test-utils.cc
@@ -55,6 +55,9 @@ TEST(Utils1) {
   CHECK_EQ(-2, -8 >> 2);
   CHECK_EQ(-2, static_cast<int8_t>(-8) >> 2);
   CHECK_EQ(-2, static_cast<int>(static_cast<intptr_t>(-8) >> 2));
+  CHECK_EQ(INT_MAX, FastD2I(1.0e100));
+  CHECK_EQ(INT_MIN, FastD2I(-1.0e100));
+  CHECK_EQ(INT_MIN, FastD2I(NAN));
 }