[memprof] Remove the "Live on exit:" print for text format.

We dropped the printing of live on exit blocks in rG1243cef245f6 -
the commit changed the insertOrMerge logic. Remove the message since it
is no longer needed (all live blocks are inserted into the hashmap)
before serializing/printing the profile. Furthermore, the original
intent was to capture evicted blocks so it wasn't entirely correct.

Also update the binary format test invocation to remove the redundant
print_text directive now that it is the default.

Differential Revision: https://reviews.llvm.org/D114285