message: Fix -Wsign-compare in OperationSupportTest.cpp
  A couple of warnings was produced when compiling this test due to comaprisons
  with a signed literal.  Used unsigned literals instead.
diff: @@ -50,11 +50,11 @@ TEST(OperandStorageTest, NonResizable) {
  // The same number of operands is okay.
  user->setOperands(operand);
  - EXPECT_EQ(user->getNumOperands(), 1);
  + EXPECT_EQ(user->getNumOperands(), 1u);
  // Removing is okay.
  user->setOperands(llvm::None);
  - EXPECT_EQ(user->getNumOperands(), 0);
  + EXPECT_EQ(user->getNumOperands(), 0u);
  // Destroy the operations.
  user->destroy();
  @@ -99,15 +99,15 @@ TEST(OperandStorageTest, Resizable) {
  // The same number of operands is okay.
  user->setOperands(operand);
  - EXPECT_EQ(user->getNumOperands(), 1);
  + EXPECT_EQ(user->getNumOperands(), 1u);
  // Removing is okay.
  user->setOperands(llvm::None);
  - EXPECT_EQ(user->getNumOperands(), 0);
  + EXPECT_EQ(user->getNumOperands(), 0u);
  // Adding more operands is okay.
  user->setOperands({operand, operand, operand});
  - EXPECT_EQ(user->getNumOperands(), 3);
  + EXPECT_EQ(user->getNumOperands(), 3u);
  // Destroy the operations.
  user->destroy();
  