[RFA] Split up testsuite/ChangeLog

[Doug Evans]

Hi.

testsuite/ChangeLog is roughly twice as big as the next biggest
changelog in all of binutils-gdb, and at 1.2M it's a monster.

If there are no objections I will split testsuite/ChangeLog into two:

ChangeLog-1993-2013 and ChangeLog

My motivation is that some code review software I use sees the large
file and chooses not to show it by default, which is an annoyance.