Revert "add return type to MemberFunctionDefinition#getNotation()"
Revert "add return type to MemberFunctionDefinition#getNotation()"

This reverts commit 016e74bc97b294b711e03d5fbbe5ba32f33106b7.

It's because it changes the behavior of the profiler result

jsx/JSX,jsx/JSX,dj31416/JSX,dj31416/JSX,jsx/JSX,dj31416/JSX,dj31416/JSX,dj31416/JSX,jsx/JSX,jsx/JSX