test-profile: allow negative time in JSON output (issue5542)

I don't know why it can be a negative number, but that shouldn't be important
here.

tests/test-profile.t

@@ -1,101 +1,101 b''
 test --time
 
   $ hg --time help -q help 2>&1 | grep time > /dev/null
   $ hg init a
   $ cd a
 
 #if lsprof
 
 test --profile
 
   $ prof='hg --config profiling.type=ls --profile'
 
   $ $prof st 2>../out
   $ grep CallCount ../out > /dev/null || cat ../out
 
   $ $prof --config profiling.output=../out st
   $ grep CallCount ../out > /dev/null || cat ../out
 
   $ $prof --config profiling.output=blackbox --config extensions.blackbox= st
   $ grep CallCount .hg/blackbox.log > /dev/null || cat .hg/blackbox.log
 
   $ $prof --config profiling.format=text st 2>../out
   $ grep CallCount ../out > /dev/null || cat ../out
 
   $ echo "[profiling]" >> $HGRCPATH
   $ echo "format=kcachegrind" >> $HGRCPATH
 
   $ $prof st 2>../out
   $ grep 'events: Ticks' ../out > /dev/null || cat ../out
 
   $ $prof --config profiling.output=../out st
   $ grep 'events: Ticks' ../out > /dev/null || cat ../out
 
 #endif
 
 #if lsprof serve
 
 Profiling of HTTP requests works
 
   $ $prof --config profiling.format=text --config profiling.output=../profile.log serve -d -p $HGPORT --pid-file ../hg.pid -A ../access.log
   $ cat ../hg.pid >> $DAEMON_PIDS
   $ hg -q clone -U http://localhost:$HGPORT ../clone
 
 A single profile is logged because file logging doesn't append
   $ grep CallCount ../profile.log | wc -l
   \s*1 (re)
 
 #endif
 
 Install an extension that can sleep and guarantee a profiler has time to run
 
   $ cat >> sleepext.py << EOF
   > import time
   > from mercurial import cmdutil, commands
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > @command('sleep', [], 'hg sleep')
   > def sleep(ui, *args, **kwargs):
   >     time.sleep(0.1)
   > EOF
 
   $ cat >> $HGRCPATH << EOF
   > [extensions]
   > sleep = `pwd`/sleepext.py
   > EOF
 
 statistical profiler works
 
   $ hg --profile sleep 2>../out
   $ grep Sample ../out
   Sample count: \d+ (re)
 
 Various statprof formatters work
 
   $ hg --profile --config profiling.statformat=byline sleep 2>../out
   $ head -n 1 ../out
     %   cumulative      self          
   $ grep Sample ../out
   Sample count: \d+ (re)
 
   $ hg --profile --config profiling.statformat=bymethod sleep 2>../out
   $ head -n 1 ../out
     %   cumulative      self          
   $ grep Sample ../out
   Sample count: \d+ (re)
 
   $ hg --profile --config profiling.statformat=hotpath sleep 2>../out
   $ grep Sample ../out
   Sample count: \d+ (re)
 
   $ hg --profile --config profiling.statformat=json sleep 2>../out
   $ cat ../out
-  \[\[\d+.* (re)
+  \[\[-?\d+.* (re)
 
 statprof can be used as a standalone module
 
   $ $PYTHON -m mercurial.statprof hotpath
   must specify --file to load
   [1]
 
   $ cd ..