Add math_expression and fix ast2 tests

tests/include/tast2.h

@@ -8,6 +8,18 @@ extern "C" {
 #define D "hello"
 #define E 'c'
 
+#define UEXPR (1234u << 1)
+#define ULEXPR (1234ul << 2)
+#define ULLEXPR (1234ull << 3)
+#define LEXPR (1234l << 4)
+#define LLEXPR (1234ll << 5)
+
+#define SHL1 (1u << 1)
+#define SHL2 (1u << 2)
+#define SHL3 (1u << 3)
+
+#define ALLSHL (SHL1 | SHL2 | SHL3)
+
 struct A0;
 struct A1 {};
 typedef struct A2;