Adapt to google::protobuf::uint64 type change

Protobuf 3.9.1 redefines google::protobuf::uint64 from unsigned long
long to uint64_t, which is sometimes unsigned long and sometimes
unsigned long long.  Use PRIu64 to print it.

Bug: 117607748
Test: m checkbuild
Exempt-From-Owner-Approval: approved at https://android-review.googlesource.com/q/Idb741c8be97df1c752083350fb8fed257903944c
Change-Id: Idb741c8be97df1c752083350fb8fed257903944c