patch 8.0.0606: cannot set the context for a specified quickfix list

Problem:    Cannot set the context for a specified quickfix list.
Solution:   Use the list index instead of the current list. (Yegappan
            Lakshmanan)

patch 8.0.0605: the quickfix cached buffer may become invalid

Problem:    The buffer that quickfix caches for performance may become
            invalid. (Daniel Hahler)
Solution:   Reset qf_last_bufref in qf_init_ext(). (Daniel Hahler,
            closes vim#1728, closes vim#1676)

patch 8.0.0604: gF test fails still on MS-Windows

Problem:    gF test fails still on MS-Windows.
Solution:   Use : before the line number and remove it from 'isfname'.

patch 8.0.0603: gF test fails on MS-Windows

Problem:    gF test fails on MS-Windows.
Solution:   Use @ instead of : before the line number

patch 8.0.0602: when gF fails to edit the file the cursor still moves

Problem:    When gF fails to edit the file the cursor still moves to the found
            line number.
Solution:   Check the return value of do_ecmd(). (Michael Hwang)

patch 8.0.0601: no test coverage for :spellrepall

Problem:    No test coverage for :spellrepall.
Solution:   Add a test. (Dominique Pelle, closes vim#1717)

patch 8.0.0600: test_recover fails on some systems

Problem:    test_recover fails on some systems.
Solution:   Explicitly check if "/" is writable. (Ken Takata)

patch 8.0.0599: diff mode is insufficiently tested

Problem:    diff mode is insufficiently tested
Solution:   Add more test cases. (Dominique Pelle, closes vim#1685)

patch 8.0.0598: building with gcc 7.1 yields new warnings

Problem:    Building with gcc 7.1 yields new warnings.
Solution:   Initialize result. (John Marriott)

patch 8.0.0597: off-by-one error in size computation

Problem:    Off-by-one error in buffer size computation.
Solution:   Use ">=" instead of ">". (Lemonboy, closes vim#1694)