MDL-45336 backup: moved the string from quiz to core

AMOS BEGIN
 CPY [timetaken,mod_quiz],[timetaken,backup]
AMOS END
MDL-45336 lesson: copied used strings from quiz

AMOS BEGIN
 CPY [false,mod_quiz],[false,mod_lesson]
 CPY [fractionsaddwrong,mod_quiz],[fractionsaddwrong,mod_lesson]
 CPY [fractionsnomax,mod_quiz],[fractionsnomax,mod_lesson]
 CPY [notenoughsubquestions,mod_quiz],[notenoughsubquestions,mod_lesson]
 CPY [true,mod_quiz],[true,mod_lesson]
AMOS END
MDL-45336 choice: removed unused code

function prepare_choice_show_results() is never called with the 5th argument,
forming of html has been moved to the renderer in MDL-20508, when function
choice_show_results() was transformed into prepare_choice_show_results() but
not all code was deleted from the funciton.
MDL-45336 scorm: copied used string from quiz

AMOS BEGIN
 CPY [deleteselected,quiz_overview],[deleteselected,mod_scorm]
AMOS END
MDL-45336 question: moved used string from quiz plugin

AMOS BEGIN
 MOV [erroritemappearsmorethanoncewithdifferentweight,quiz_statistics],[erroritemappearsmorethanoncewithdifferentweight,question]
AMOS END