Revert "libmediautils: pin cpp_std to gnu++17"

This reverts commit aa40f89b94471b234e8af39dfcae37b4a5191878.

Reason for revert: Patch was temporary until b/311679534 resolved

Change-Id: I6b8c6204d88b37e48749f36f26d9ec2351dfb43a
1 file changed