support/testing: don't use TestPythonPackageBase.config and linaro toolchain

support/testing: don't use TestPythonPackageBase.config and linaro toolchain

TestPythonPackageBase.config provide already the basic uClibc toolchain.
So by adding the symbols for the linaro toolchain some warning are printed
at while loading the configuration:

.config:16:warning: override: reassigning to symbol BR2_TOOLCHAIN_EXTERNAL
.config:16:warning: override: BR2_TOOLCHAIN_EXTERNAL changes choice state
.config:17:warning: override: reassigning to symbol BR2_TARGET_ROOTFS_CPIO
.config:21:warning: override: BR2_TOOLCHAIN_EXTERNAL_LINARO_ARM changes choice state

So, some symbol disapear from the generated dot config (.config) leading
to an error due to a new check in the testsuite infra.

Since this test should use the Linaro toolchain, remove
TestPythonPackageBase.config add BR2_arm=y and disable the rootfs tar option.

While at it, re-order the options so that they appear in the same
order as they appear in a defconfig.

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Cc: Adam Duskett <Aduskett@gmail.com>
Cc: Yann E. MORIN <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>