GSI: enable dynamic partitions

to facilitate mixing GSI onto Cuttlefish

Bug: 178677060
Bug: 179455901
Test: build gsi_x86_64 and aosp_arm64 and check the existence of
      'dynamic_partition_list' in misc_info.txt

Change-Id: I0fd9e9645d4882e2cd7d3508a44fbcad5dce81bc