hw/i386/pc: Remove deprecated pc-q35-2.7 and pc-i440fx-2.7 machines

hw/i386/pc: Remove deprecated pc-q35-2.7 and pc-i440fx-2.7 machines

These machines has been supported for a period of more than 6 years.
According to our versioned machine support policy (see commit
ce80c4fa6ff "docs: document special exception for machine type
deprecation & removal") they can now be removed.  Remove the qtest
in test-x86-cpuid-compat.c file.

Reviewed-by: Mark Cave-Ayland <mark.caveayland@nutanix.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20260108033051.777361-21-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>