[turbofan] Add RoundUint32ToFloat32 operator to Turbofan.

test/cctest/compiler/test-run-machops.cc

Index: test/cctest/compiler/test-run-machops.cc
diff --git a/test/cctest/compiler/test-run-machops.cc b/test/cctest/compiler/test-run-machops.cc
index 52672c8a89204cdf1fcc7d275311813bbeaf9a46..dc7a0fbdc4608be80a0a8a9e84f00e69ba2b0fd6 100644
--- a/test/cctest/compiler/test-run-machops.cc
+++ b/test/cctest/compiler/test-run-machops.cc
@@ -6020,6 +6020,13 @@ TEST(RunRoundInt32ToFloat32) {
 }
 
 
+TEST(RunRoundUint32ToFloat32) {
+  BufferedRawMachineAssemblerTester<float> m(MachineType::Uint32());
+  m.Return(m.RoundUint32ToFloat32(m.Parameter(0)));
+  FOR_UINT32_INPUTS(i) { CHECK_EQ(static_cast<float>(*i), m.Call(*i)); }
+}
+
+
 TEST(RunBitcastInt32ToFloat32) {
   int32_t input = 1;
   float output = 0.0;