There are many tests in the test suite that output the same message as other tests in the same test file.

We should make each output unique, to facilitate test identification, as well
as helping with test case result analysis/comparison.

$ cat testsuite/gdb.sum | grep "gdb..*:" | sed 's/[A-Z]\+: //g' | sort | uniq -c | sort -n | grep -v "^\( \)*1 " | wc -l
1263

That means there are currently 1263 outputs in gdb.sum that are not unique.  That was on amd64-linux-linux.

The top 20 of worse offenders is:

$ cat testsuite/gdb.sum | grep "gdb..*:" | sed 's/[A-Z]\+: //g' | sort | uniq -c | sort -n | tail -n 20

      7 gdb.python/py-value.exp: get value from history
      8 gdb.python/py-template.exp: print foo
      8 gdb.python/py-template.exp: python foo = gdb.history(0)
      8 gdb.python/py-type.exp: get value from history
      9 gdb.base/call-sc.exp: return foo; synchronize pc to main()
      9 gdb.base/call-sc.exp: set print address off
      9 gdb.base/call-sc.exp: set print sevenbit-strings
      9 gdb.base/call-sc.exp: set width 0
      9 gdb.python/py-breakpoint.exp: continue to breakpoint: Break at multiply.
     10 gdb.base/checkpoint.exp: restart 1 three
     10 gdb.base/relational.exp: set variable x
     11 gdb.base/relational.exp: set variable z
     11 gdb.python/py-type.exp: print value
     15 gdb.base/dump.exp: print zero_all ()
     24 gdb.base/structs.exp: set print address off
     24 gdb.base/structs.exp: set print elements 300
     24 gdb.base/structs.exp: set print sevenbit-strings
     24 gdb.base/structs.exp: set width 0
     26 gdb.reverse/sigall-precsave.exp: reverse signal delivered
     26 gdb.reverse/sigall-reverse.exp: reverse signal delivered

The first column indicates how often is the output message repeated in gdb.sum.

And here's the distribution:

$ cat testsuite/gdb.sum | grep "gdb..*:" | sed 's/[A-Z]\+: //g' | sort | uniq -c | sort -n | awk ' { print $1 } ' | uniq -c
  18636 1
   1129 2
     55 3
     41 4
      8 5
      6 6
      5 7
      3 8
      5 9
      2 10
      2 11
      1 15
      4 24
      2 26

Unfortunately, by far, we have many cases of the same output appearing twice.