Removes unused mypyc imports (#11237)

Author: sobolevn

mypyc/common.py

@@ -1,5 +1,4 @@
 from mypy.util import unnamed_function
-import sys
 from typing import Dict, Any, Optional, Tuple
 import sys
 

mypyc/irbuild/prepare.py

@@ -14,9 +14,9 @@
 from typing import List, Dict, Iterable, Optional, Union, DefaultDict, NamedTuple, Tuple
 
 from mypy.nodes import (
-    MypyFile, TypeInfo, FuncDef, ClassDef, Decorator, OverloadedFuncDef, MemberExpr, Var,
-    Expression, SymbolNode, ARG_STAR, ARG_STAR2, CallExpr, Decorator, Expression, FuncDef,
-    MemberExpr, MypyFile, NameExpr, RefExpr, TypeInfo,
+    ClassDef, OverloadedFuncDef, Var,
+    SymbolNode, ARG_STAR, ARG_STAR2, CallExpr, Decorator, Expression, FuncDef,
+    MemberExpr, MypyFile, NameExpr, RefExpr, TypeInfo
 )
 from mypy.types import Type, Instance, get_proper_type
 from mypy.build import Graph