Fix bugs that the libc++ test suite found in the handling of dependent exceptions.
Fix bugs that the libc++ test suite found in the handling of dependent exceptions.

sudosurootdev/external_libcxxrt,xin3liang/platform_external_libcxxrt,sudosurootdev/external_libcxxrt,sudosurootdev/external_libcxxrt,cemeyer/libcxxrt,xin3liang/platform_external_libcxxrt,vegard/libcxxrt,vegard/libcxxrt,vegard/libcxxrt,cemeyer/libcxxrt,xin3liang/platform_external_libcxxrt,cemeyer/libcxxrt