tests: add some helpful `|| cat` bits to test-profile.t

This way if the hg invocation crashes, you get to see a stacktrace
without having to edit the test.

Differential Revision: https://phab.mercurial-scm.org/D5208

tests/test-profile.t

@@ -86,22 +86,22 b' statistical profiler works'
 
 Various statprof formatters work
 
-  $ hg --profile --config profiling.statformat=byline sleep 2>../out
+  $ hg --profile --config profiling.statformat=byline sleep 2>../out || cat ../out
   $ head -n 3 ../out
     %   cumulative      self          
    time    seconds   seconds  name    
    * sleepext.py:*:sleep (glob)
   $ cat ../out | statprofran
 
-  $ hg --profile --config profiling.statformat=bymethod sleep 2>../out
+  $ hg --profile --config profiling.statformat=bymethod sleep 2>../out || cat ../out
   $ head -n 1 ../out
     %   cumulative      self          
   $ cat ../out | statprofran
 
-  $ hg --profile --config profiling.statformat=hotpath sleep 2>../out
+  $ hg --profile --config profiling.statformat=hotpath sleep 2>../out || cat ../out
   $ cat ../out | statprofran
 
-  $ hg --profile --config profiling.statformat=json sleep 2>../out
+  $ hg --profile --config profiling.statformat=json sleep 2>../out || cat ../out
   $ cat ../out
   \[\[-?\d+.* (re)