patch 8.2.2587: recover test fails on FreeBSD

Problem:    Recover test fails on FreeBSD.
Solution:   Check for Linux.

src/testdir/check.vim

@@ -84,8 +84,16 @@ func CheckUnix()
   endif
 endfunc
 
+" Command to check for running on Linix
+command CheckLinux call CheckLinux()
+func CheckLinux()
+  if !has('linux')
+    throw 'Skipped: only works on Linux'
+  endif
+endfunc
+
 " Command to check for not running on a BSD system.
-" TODO: using this checks should not be needed
+" TODO: using this check should not be needed
 command CheckNotBSD call CheckNotBSD()
 func CheckNotBSD()
   if has('bsd')

src/testdir/test_recover.vim

@@ -79,8 +79,9 @@ func Test_swap_file()
 endfunc
 
 func Test_nocatch_process_still_running()
-  " assume Unix means sysinfo.uptime can be used
-  CheckUnix
+  " sysinfo.uptime probably only works on Linux
+  CheckLinux
+  " the GUI dialog can't be handled
   CheckNotGui
 
   " don't intercept existing swap file here

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2587,
 /**/
     2586,
 /**/