validate: flow: Ignore trailing white spaces while checking

Fix gstreamer / validate.simplest unit test failure on Windows
41 jobs for win-fix in 45 minutes and 44 seconds (queued for 5 seconds)
latest
Status Job ID Name Coverage
  Build Docker
passed #4527290
alpine amd64 manifest builder docker

00:00:29

passed #4527289
android docker

00:01:38

passed #4527288
cerbero fedora amd64 docker

00:01:43

passed #4527287
fedora amd64 docker

00:01:48

passed #4527291
gst-indent amd64 docker

00:00:33

 
  Preparation
passed #4527293
gst indent

00:00:17

passed #4527292
manual
manifest

00:00:16

 
  Build
passed #4527302
gstreamer
build cerbero cross-android universal

00:14:03

passed #4527306
gst-ios-13.2
build cerbero cross-ios universal

00:23:37

passed #4527303
gstreamer
build cerbero cross win32

00:10:01

passed #4527304
gstreamer
build cerbero cross win64

00:07:33

passed #4527301
gstreamer
build cerbero fedora x86_64

00:07:01

passed #4527305
gst-macos-10.15
build cerbero macos x86_64

00:11:10

passed #4527297
build clang fedora x86_64

00:15:01

manual #4527300
1809 windows docker allowed to fail manual
build msys2
passed #4527294
build nodebug fedora x86_64

00:12:07

passed #4527295
build static fedora x86_64

00:12:47

passed #4527296
build static nodebug fedora x86_64

00:11:09

passed #4527298
1809 windows docker
build vs2017 amd64

00:08:32

passed #4527299
1809 windows docker
build vs2017 x86

00:07:29

 
  Test
passed #4527834
gstreamer
check fedora

00:05:33

passed #4527308
gstreamer
integration testsuites fedora 1/4

00:15:23

passed #4527309
gstreamer
integration testsuites fedora 2/4

00:14:27

passed #4527310
gstreamer
integration testsuites fedora 3/4

00:12:55

passed #4527311
gstreamer
integration testsuites fedora 4/4

00:15:25

passed #4527322
gstreamer
local valgrind bad

00:05:12

passed #4527319
gstreamer
local valgrind base

00:07:42

passed #4527318
gstreamer
local valgrind core

00:06:23

passed #4527323
gstreamer
local valgrind ges

00:06:14

passed #4527320
gstreamer
local valgrind good

00:07:18

passed #4527321
gstreamer
local valgrind ugly

00:04:23

passed #4527316
gstreamer
valgrind bad

00:06:11

passed #4527313
gstreamer
valgrind base

00:11:55

passed #4527312
gstreamer
valgrind core

00:13:44

passed #4527317
gstreamer
valgrind ges

00:06:35

passed #4527314
gstreamer
valgrind good

00:12:11

passed #4527315
gstreamer
valgrind ugly

00:03:55

failed #4527307
gstreamer
check fedora

00:11:18

 
  Integrate
passed #4527324
cross-android universal examples

00:09:54

passed #4527326
gst-ios-13.2
cross-ios universal examples

00:02:18

passed #4527325
documentation

00:19:25