andyzhangx: test: fix unstable e2e tests which check file content

JobBuild
1341
05-18 01:29
pull-azuredisk-csi-driver-e2e-capz 1526957006726893568 1526736744370671616
pull-azuredisk-csi-driver-e2e-capz-windows-2019 1526957005892227072 1526736743540199424
pull-azuredisk-csi-driver-e2e-migration 1526957004482940928 1526736742097358848
pull-azuredisk-csi-driver-e2e-migration-windows 1526957004516495360 1526753162789130240 1526736742143496192
pull-azuredisk-csi-driver-e2e-multi-az 1526957004420026368 1526736742051221504
pull-azuredisk-csi-driver-e2e-single-az 1526957004382277632 1526736742009278464
pull-azuredisk-csi-driver-e2e-windows-containerd 1526957005049171968 1526736742697144320
pull-azuredisk-csi-driver-external-e2e-single-az 1526957004600381440 1526736742218993664
pull-azuredisk-csi-driver-integration 1526957004340334592 1526736741967335424
pull-azuredisk-csi-driver-sanity 1526957004302585856 1526736741925392384
pull-azuredisk-csi-driver-unit 1526957004252254208 1526736741891837952
pull-azuredisk-csi-driver-verify 1526957004210311168 1526736741854089216
pull-azuredisk-csi-driver-windows-build 1526957004554244096 1526736742177050624