simpleperf: use file records in protobuf output.

simpleperf: use file records in protobuf output.

Dump file name and symbol name for each CallChainEntry
takes too much space. So instead we store file_id and
symbol_id for each CallChainEntry, and store file
records separately.

In CallChainEntry, replace ip with vaddr_in_file, because
vaddr_in_file is more useful in finding instructions in
elf file.

Bug: http://b/32210800
Test: simpleperf_unit_test.
Change-Id: I85542db21acbaa4d81b3c3aa7f9215f2d23c4878