Fix test code to work on some environments. const char * is more preferable than string for ifstream constructor.
Fix test code to work on some environments.
const char * is more preferable than string for ifstream constructor.

videolabs/taglib,Distrotech/taglib,Distrotech/taglib,dlz1123/taglib,dlz1123/taglib,i80and/taglib,davispuh/taglib,TsudaKageyu/taglib,Distrotech/taglib,davispuh/taglib,black78/taglib,i80and/taglib,i80and/taglib,black78/taglib,pbhd/taglib,MaxLeb/taglib,davispuh/taglib,TsudaKageyu/taglib,black78/taglib,videolabs/taglib,videolabs/taglib,pbhd/taglib,dlz1123/taglib,taglib/taglib,MaxLeb/taglib,taglib/taglib,MaxLeb/taglib,TsudaKageyu/taglib,pbhd/taglib,taglib/taglib