Expose timestats.proto to the java host library

Bug: 142712295
Test: Add host-timestats-proto to an Android.mk file
Test: which is used to build the java file referencing
Test: the timestats.proto
Test: Eg. vendor/google_testing/tvts/urils/Android.mk
Test: replace utils-proto with host-timestats-proto
Test: Remove the duplicate proto file used in utils-proto
Test: Confirm the java file works as it did before.
Change-Id: If04539d959c2a517d6e2ec4338e0290651c03b89