simpleperf: keep binary in class Record.

It removes memory copy and heap allocation/deallocation in
Record::BinaryFormat(), and is a preparation to remove memory
copy and heap allocation in Record constructor.

Bug: 30649868
Test: run simpleperf_unit_test.
Change-Id: Ic8dd80e43f7b547a9beaf896d726b56aeb5d55a2
16 files changed