support/testing: test_clang: update to the next LTS kernel (4.19.x)

The kernel 4.16.7 curently used by the test doesn't build with host
bison (GNU Bison 3.7.5) probably due a missing fix [1] in 4.16.x branch.

Since kernel 4.16 is EOL, bump to the next LTS kernel (4.19.x) in order
to ease backport to previous Buildroot releases.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/4114986744

[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d59fbbd09d5d6bdf4ea1f0b4090d175e081ff421

Signed-off-by: Romain Naour <romain.naour@smile.fr>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

support/testing/tests/package/test_clang.py

@@ -14,7 +14,7 @@ class TestClangCompilerRT(infra.basetest.BRTest):
         BR2_TARGET_GENERIC_GETTY_PORT="ttyAMA0"
         BR2_LINUX_KERNEL=y
         BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-        BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.16.7"
+        BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="4.19.283"
         BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
         BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/aarch64-virt/linux.config"
         BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y