patch 8.2.5158: TSTP and INT signal tests are not run with valgrind

Problem:    TSTP and INT signal tests are not run with valgrind.
Solution:   Sleep a bit longer. (closes #10614)
diff --git a/src/testdir/test_signals.vim b/src/testdir/test_signals.vim
index 2cf0dd7..b7a8b28 100644
--- a/src/testdir/test_signals.vim
+++ b/src/testdir/test_signals.vim
@@ -85,20 +85,15 @@
     throw 'Skipped: INT signal not supported'
   endif
 
-  " Skip the test when running with valgrind as signal INT is not received
-  " somehow by Vim when running with valgrind.
-  let cmd = GetVimCommand()
-  if cmd =~ 'valgrind'
-    throw 'Skipped: cannot test signal INT with valgrind'
-  endif
-
   let buf = RunVimInTerminal('', {'rows': 6})
   let pid_vim = term_getjob(buf)->job_info().process
 
   " Check that an endless loop in Vim is interrupted by signal INT.
+  call term_sendkeys(buf, ":call setline(1, 'running')\n")
   call term_sendkeys(buf, ":while 1 | endwhile\n")
   call WaitForAssert({-> assert_equal(':while 1 | endwhile', term_getline(buf, 6))})
   exe 'silent !kill -s INT ' .. pid_vim
+  sleep 50m
   call term_sendkeys(buf, ":call setline(1, 'INTERRUPTED')\n")
   call WaitForAssert({-> assert_equal('INTERRUPTED', term_getline(buf, 1))})
 
@@ -112,13 +107,6 @@
     throw 'Skipped: TSTP signal not supported'
   endif
 
-  " Skip the test when running with valgrind as signal TSTP is not received
-  " somehow by Vim when running with valgrind.
-  let cmd = GetVimCommand()
-  if cmd =~ 'valgrind'
-    throw 'Skipped: cannot test signal TSTP with valgrind'
-  endif
-
   " If test fails once, it can leave temporary files and trying to rerun
   " the test would then fail again if they are not deleted first.
   call delete('.Xsig_TERM.swp')
@@ -142,9 +130,10 @@
   exe 'silent !kill -s TSTP ' .. pid_vim
   call WaitForAssert({-> assert_true(filereadable('.Xsig_TERM.swp'))})
 
-  " We resume after the suspend
+  " We resume after the suspend.  Sleep a bit for the signal to take effect,
+  " also when running under valgrind. 
   exe 'silent !kill -s CONT ' .. pid_vim
-  exe 'silent !sleep 0.006'
+  sleep 100m
 
   call StopVimInTerminal(buf)