Add missing test file

test/output_alias.cpp

+#include <migraph/program.hpp>
+#include <migraph/instruction.hpp>
+#include <test.hpp>
+#include <basic_ops.hpp>
+
+
+void simple_alias()
+{
+    migraph::program p;
+    auto l = p.add_literal(1);
+    auto p1 = p.add_instruction(pass_op{}, l);
+    EXPECT(bool{migraph::instruction::get_output_alias(l) == l});
+    EXPECT(bool{migraph::instruction::get_output_alias(p1) == l});
+}
+
+void cascade_alias()
+{
+    migraph::program p;
+    auto l = p.add_literal(1);
+    auto p1 = p.add_instruction(pass_op{}, l);
+    auto p2 = p.add_instruction(pass_op{}, p1);
+    auto p3 = p.add_instruction(pass_op{}, p2);
+    EXPECT(bool{migraph::instruction::get_output_alias(l) == l});
+    EXPECT(bool{migraph::instruction::get_output_alias(p1) == l});
+    EXPECT(bool{migraph::instruction::get_output_alias(p2) == l});
+    EXPECT(bool{migraph::instruction::get_output_alias(p3) == l});
+}
+
+void no_alias()
+{
+    migraph::program p;
+    auto x = p.add_literal(1);
+    auto y = p.add_literal(2);
+    auto sum = p.add_instruction(sum_op{}, x, y);
+    EXPECT(bool{migraph::instruction::get_output_alias(sum) == sum});
+}
+
+int main() {
+    simple_alias();
+    cascade_alias();
+    no_alias();
+}