Add cst_var_binop.py as passing assign test

tests/passing_tests/assign/cst_var_binop.py

@@ -0,0 +1,27 @@
+from pythonbpf import bpf, section, bpfglobal, compile
+from ctypes import c_void_p, c_int64
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_execve")
+def hello_world(ctx: c_void_p) -> c_int64:
+    x = 1
+    print(f"Initial x: {x}")
+    a = 20
+    x = a
+    print(f"Updated x with a: {x}")
+    x = (x + x) * 3
+    if x == 2:
+        print("Hello, World!")
+    else:
+        print(f"Goodbye, World! {x}")
+    return
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()