don't do miscellanea/install_kernel_tools_testing if using test kernel

miscellanea/check_prerelease case already point out the test kernel.

miscellanea/install_kernel_tools_testing shouldn't report it failed.
Instead, it needs to detect and skip to reduce the noise.

BTW, it seesm can be removed because:

commit d2e39e350f3d1b37ccc1b573bf166881e7d05cbe
Author: Alex Tu <email address hidden>
Date: Mon Apr 26 13:17:11 2021 +0800

    move linux-tools installation from ppc to pc-sanity temporarily

    for https://code.launchpad.net/~alextu/plainbox-provider-checkbox/+git/plainbox-provider-checkbox/+merge/388726
    It's not accepted to install packages in test cases.
    So, we need to install linux-tools before testing.
    The final goal would be install the packages before checkbox testing.
    e.g. prepare-checkbox-sanity or testflinger yaml.

    This change is to make sure linux-tools be installed before we achived the final
    goal.

diff --git a/units/pc-sanity/pc-sanity-misc.pxu b/units/pc-sanity/pc-sanity-misc.pxu
index 860e6cd..47ad58a 100644
--- a/units/pc-sanity/pc-sanity-misc.pxu
+++ b/units/pc-sanity/pc-sanity-misc.pxu
@@ -1,3 +1,16 @@
+plugin: shell
+category_id: com.canonical.plainbox::miscellanea
+requires:
+ device.category == 'NETWORK'
+ package.name == 'checkbox-ng'
+estimated_duration: 20
+id: miscellanea/install_kernel_tools_testing
+user: root
+command:
+ dpkg -s linux-tools-"$(uname -r)" || apt-get install -y linux-tools-"$(uname -r)" || exit 1
+_summary: Install linux-tools based on the running kernel version.
+_description: Install linux-tools based on the running kernel version.
+
 plugin: shell
 id: misc/generic/grub_boothole
 user: root
diff --git a/units/pc-sanity/pc-sanity.pxu b/units/pc-sanity/pc-sanity.pxu
index 9e67f0a..9d584f8 100644
--- a/units/pc-sanity/pc-sanity.pxu
+++ b/units/pc-sanity/pc-sanity.pxu
@@ -13,6 +13,7 @@ include:
     com.canonical.certification::miscellanea/cvescan
     com.canonical.certification::miscellanea/check-nvidia
     com.canonical.certification::miscellanea/debsums
+ com.canonical.certification::miscellanea/install_kernel_tools_testing
     com.canonical.certification::power-management/check-turbostat-long-idle-cpu-residency
     com.canonical.certification::power-management/check-turbostat-long-idle-s0ix-residency
     com.canonical.certification::power-management/check-turbostat-long-idle-gfxrc6-residency