tests/functional: Fix reverse_debugging asset precaching

This commit fixes the asset precaching in the reverse_debugging test on
aarch64.

QemuBaseTest.main() precaches assets (kernel, rootfs, DT blobs, etc.)
that are defined in variables with the ASSET_ prefix. This works because
it ultimately calls Asset.precache_test(), which relies on introspection
to locate these variables.

If an asset variable is not named with the ASSET_ prefix, precache_test
cannot find the asset and precaching silently fails. Hence, fix the
asset precaching by fixing the asset variable name.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Message-ID: <20250827001008.22112-1-gustavo.romero@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit 36fb979666)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

tests/functional/test_aarch64_reverse_debug.py

@@ -21,7 +21,7 @@ class ReverseDebugging_AArch64(ReverseDebugging):
 
     REG_PC = 32
 
-    KERNEL_ASSET = Asset(
+    ASSET_KERNEL = Asset(
         ('https://archives.fedoraproject.org/pub/archive/fedora/linux/'
          'releases/29/Everything/aarch64/os/images/pxeboot/vmlinuz'),
         '7e1430b81c26bdd0da025eeb8fbd77b5dc961da4364af26e771bd39f379cbbf7')
@@ -30,7 +30,7 @@ class ReverseDebugging_AArch64(ReverseDebugging):
     def test_aarch64_virt(self):
         self.set_machine('virt')
         self.cpu = 'cortex-a53'
-        kernel_path = self.KERNEL_ASSET.fetch()
+        kernel_path = self.ASSET_KERNEL.fetch()
         self.reverse_debugging(args=('-kernel', kernel_path))