Linux kernel 5.4 changes, UNIT TESTING

### Guest:
OpenSuse 15.1
Linux linux-hzpw 4.12.14-lp151.28.16-default #1 SMP Wed Sep 18 05:32:19 UTC 2019 (3e458e0) x86_64 x86_64 x86_64 GNU/Linux

### Host:
Fedora Rawhide/32
Linux lserver 5.4.0-0.rc2.git1.1.fc32.x86_64 #1 SMP Tue Oct 8 17:04:36 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

VirtualBox VM 6.1.0_BETA1 r133811 linux.amd64 (Oct 10 2019 09:49:04) release log
Oracle VM VirtualBox Extension Pack (Version: 6.1.0_BETA1 r133811; VRDE Module: VBoxVRDP)
Oracle VBoxDTrace Extension Pack (Version: 6.1.0_BETA1 r133811; VRDE Module: )

### Guest extensions inside the guest:

[   22.749207] 11:35:01.283942 main     VBoxService 6.1.0_BETA1 r133811 (verbosity: 0) linux.amd64 (Oct 10 2019 09:43:44) release log
               11:35:01.283953 main     Log opened 2019-10-10T11:35:01.283915000Z
[   22.749392] 11:35:01.284279 main     OS Product: Linux
[   22.749528] 11:35:01.284431 main     OS Release: 4.12.14-lp151.28.16-default
[   22.749699] 11:35:01.284565 main     OS Version: #1 SMP Wed Sep 18 05:32:19 UTC 2019 (3e458e0)
[   22.749880] 11:35:01.284735 main     Executable: /opt/VBoxGuestAdditions-6.1.0_BETA1/sbin/VBoxService
               11:35:01.284740 main     Process ID: 1653
               11:35:01.284743 main     Package type: LINUX_64BITS_GENERIC
[   22.762062] 11:35:01.296869 main     6.1.0_BETA1 r133811 started. Verbose level = 0
[   22.767379] 11:35:01.302153 main     vbglR3GuestCtrlDetectPeekGetCancelSupport: Supported (#1)
[   22.788519] vboxsf: g_fHostFeatures=0x8000000f g_fSfFeatures=0x1 g_uSfLastFunction=29
[   22.788693] vboxsf: Successfully loaded version 6.1.0_BETA1
[   22.788751] vboxsf: Successfully loaded version 6.1.0_BETA1 on 4.12.14-lp151.28.16-default SMP mod_unload modversions  (LINUX_VERSION_CODE=0x40c0e)
[   22.789659] 11:35:01.324602 automount vbsvcAutomounterMountIt: Successfully mounted 'Downloads' on '/media/sf_Downloads'
[   32.937984] [drm:vmw_sou_crtc_page_flip [vmwgfx]] *ERROR* Page flip error -16.

XXX doing this 2nd cut+paste from guest to host the guest aborted XXX2
[  913.800982] [drm:vmw_sou_crtc_page_flip [vmwgfx]] *ERROR* Page flip error -16.

### functionality:

shared clipboard host->guest works
shared clipboard guest-> host works with Problems
shared folder host->guest works r/w
shared folder guest->host works r/w

### Problems:
XXX1
00:25:50.070813 GUI: UIMachineLogic: Guest-screen count changed
00:25:59.885176 Shared clipboard: Initializing X11 clipboard backend
00:25:59.891634 Shared clipboard: Starting shared clipboard thread
00:25:59.920291 VMMDev: Guest Additions capability report: (0x4 -> 0x5) seamless: yes, hostWindowMapping: no, graphics: yes
00:25:59.920587 GUI: UISession::sltAdditionsChange: GA state really changed, notifying listeners
00:25:59.920621 GUI: UIMachineViewNormal::adjustGuestScreenSize: Adjust guest-screen size if necessary
00:25:59.920646 GUI: UISession::sltAdditionsChange: GA state change event came, notifying listeners
00:25:59.920652 GUI: UIMachineLogicNormal::sltCheckForRequestedVisualStateType: Requested-state=0, Machine-state=5
00:28:05.716690 Shared clipboard: Initializing X11 clipboard backend
00:28:05.723501 Shared clipboard: Starting shared clipboard thread
00:28:20.148496 
00:28:20.148497 !!Assertion Failed!!
00:28:20.148498 Expression: RT_SUCCESS_NP(rc2)
00:28:20.148499 Location  : /home/ws/vb54/trunk/src/VBox/HostServices/SharedClipboard/VBoxSharedClipboardSvc-x11.cpp(77) void ClipReportX11FormatsCallback(SHCLCONTEXT*, uint32_t)
00:28:20.148520 Stack     :
00:28:20.148520 00007f8e7c6cf57a VBoxRT.so!RTAssertMsg2V+0x47f (rva:0x2ed57a)
00:28:20.148521 
00:28:20.148565 VERR_CANCELLED (-70) - The operation was cancelled by the user (copy) or another thread (local ipc).

=> VBox.log-clipboard-failure

XXX2

=> VBox.log-clipboard-failure-2

00:15:17.066865 VMMDev: Guest Additions capability report: (0x4 -> 0x5) seamless: yes, hostWindowMapping: no, graphics: yes
00:15:17.067763 GUI: UISession::sltAdditionsChange: GA state really changed, notifying listeners
00:15:17.068170 GUI: UIMachineViewNormal::adjustGuestScreenSize: Adjust guest-screen size if necessary
00:15:17.068744 GUI: UISession::sltAdditionsChange: GA state change event came, notifying listeners
00:15:17.068849 GUI: UIMachineLogicNormal::sltCheckForRequestedVisualStateType: Requested-state=0, Machine-state=5
00:15:17.078681 Shared clipboard: Initializing X11 clipboard backend
00:15:17.086402 Shared clipboard: Starting shared clipboard thread
00:20:08.288042 Shared clipboard: Initializing X11 clipboard backend
00:20:08.294878 Shared clipboard: Starting shared clipboard thread
00:20:43.957787 
00:20:43.957788 !!Assertion Failed!!
00:20:43.957789 Expression: RT_SUCCESS_NP(rc2)
00:20:43.957790 Location  : /home/ws/vb54/trunk/src/VBox/HostServices/SharedClipboard/VBoxSharedClipboardSvc-x11.cpp(77) void ClipReportX11FormatsCallback(SHCLCONTEXT*, uint32_t)
00:20:43.957812 Stack     :
00:20:43.957812 00007f18aee8a57a VBoxRT.so!RTAssertMsg2V+0x47f (rva:0x2ed57a)
00:20:43.957812 
00:20:43.957852 VERR_CANCELLED (-70) - The operation was cancelled by the user (copy) or another thread (local ipc).


### Guest
Winows 10_1903_V1

### functionality:

shared clipboard host->guest works
shared clipboard guest-> host works
shared folder host->guest works r/w
shared folder guest->host works r/w