Add classloader for RtlCompatibleViewPager

To avoid BadParcelableException when reload the activity after it
is killed by OS.

Bug: 31707097
Test: make SettingsTests && adb install -r \
${OUT}/data/app/SettingsTests/SettingsTests.apk && \
adb shell am instrument -w \
'com.android.settings.tests/android.support.test.runner.AndroidJUnitRunner'

Change-Id: Ic8f20d9e2d236f0bea96071a88fbc6e7ba856f54