invalid_file_test: convert test param from tuple to struct

fixes visual studio 9 + apple clang builds where the template type is
interpreted as char[] rather than const char*:

::f1_' : cannot specify explicit initializer for arrays
error: array initializer must be an initializer list or string literal

Change-Id: I27286ce341b2f7a09b6202caffd6b72f64fd2234
1 file changed