meson: remove unneeded py3

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220323155743.1585078-4-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/meson.build

@@ -1,5 +1,3 @@
-py3 = import('python').find_installation()
-
 subdir('bench')
 subdir('qemu-iotests')