Revert "Create Multi-HAL 2.1 service"

Revert submission 10501254-multihal_2_1



Reason for revert: Droidcop: Potential culprit for b/155328660 - verifying through Forrest before revert submission. This is part of the standard investigation process, and does not mean your CL will be reverted.
Bug: 155328660
Reverted Changes:
I2be51568b:Update tests for multihal to test HAL 2.1
Id5ab7b606:Create Multi-HAL 2.1 service
Icefae8c12:Set up Multi-HAL for Sensors HAL 2.1

Change-Id: I5e828d1dfd4f9ede5cbd38ff8bc4cc5dc48e4d76