Switch to system user before CtsBackupTestCases and
CtsBackupHostTestCases module

Backup tests are not fully supported in secondary user and only works
for system users. Tests in this module will fail for devices in headless
user mode which by default runs in secondary user, such as automotive
devices.

Bug: 130183386, Bug: 130185764
Test: atest CtsBackupTestCases, atest CtsBackupHostTestCases
Change-Id: Ic85de6f9d1a536522d0acb3524c96b72caf4d40b
2 files changed