[arm64][turbofan] Do not use ubfx for shr+and combination for mask=0.

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 650098aee4aa4b3819329d6703c26be7b23ac9ea..146d8dc4132a4d508b25d859a6d1d54f251c7b65 100644
--- a/test/cctest/compiler/test-run-machops.cc
+++ b/test/cctest/compiler/test-run-machops.cc
@@ -6739,6 +6739,20 @@ TEST(Regression5951) {
   CHECK_EQ(input, m.Call(input));
 }
 
+TEST(Regression6046a) {
+  BufferedRawMachineAssemblerTester<int64_t> m;
+  m.Return(m.Word64Shr(m.Word64And(m.Int64Constant(0), m.Int64Constant(0)),
+                       m.Int64Constant(64)));
+  CHECK_EQ(0, m.Call());
+}
+
+TEST(Regression6046b) {
+  BufferedRawMachineAssemblerTester<int32_t> m;
+  m.Return(m.Word32Shr(m.Word32And(m.Int32Constant(0), m.Int32Constant(0)),
+                       m.Int32Constant(32)));
+  CHECK_EQ(0, m.Call());
+}
+
 #endif  // V8_TARGET_ARCH_64_BIT
 
 TEST(Regression6028) {