[lldb] Use APSInt's right shift operator in Scalar (#160149)

Right shift operator in `Scalar` didn't check if the value is unsigned
to perform a logical right shift. Use the right shift operator from
`APSInt` that does this check.

Author: kuilpd

lldb/source/Utility/Scalar.cpp

@@ -471,24 +471,10 @@ bool Scalar::ShiftRightLogical(const Scalar &rhs) {
 }
 
 Scalar &Scalar::operator>>=(const Scalar &rhs) {
-  switch (m_type) {
-  case e_void:
-  case e_float:
+  if (m_type == e_int && rhs.m_type == e_int)
+    m_integer >>= rhs.m_integer.getZExtValue();
+  else
     m_type = e_void;
-    break;
-
-  case e_int:
-    switch (rhs.m_type) {
-    case e_void:
-    case e_float:
-      m_type = e_void;
-      break;
-    case e_int:
-      m_integer = m_integer.ashr(rhs.m_integer);
-      break;
-    }
-    break;
-  }
   return *this;
 }
 

lldb/unittests/Utility/ScalarTest.cpp

@@ -118,11 +118,17 @@ TEST(ScalarTest, RightShiftOperator) {
   int a = 0x00001000;
   int b = 0xFFFFFFFF;
   int c = 4;
+  unsigned d = 0xFFFFFFFF;
+  unsigned short e = 0xFFFF;
   Scalar a_scalar(a);
   Scalar b_scalar(b);
   Scalar c_scalar(c);
+  Scalar d_scalar(d);
+  Scalar e_scalar(e);
   ASSERT_EQ(a >> c, a_scalar >> c_scalar);
   ASSERT_EQ(b >> c, b_scalar >> c_scalar);
+  ASSERT_EQ(d >> c, d_scalar >> c_scalar);
+  ASSERT_EQ(e >> c, e_scalar >> c_scalar);
 }
 
 TEST(ScalarTest, GetBytes) {