Simpleperf: Add SPLIT and SPLIT_END records to handle big records.

Previously we split KernelSymbolRecord because it is > 65535. Then
I found TracingDataRecord can also be > 65535. So it is better to
handle big records when reading and writing perf.data.
record_file_writer.cpp splits a big record into multiple SPLIT
records followed by a SPLIT_END record, and record_file_reader.cpp
restores the big record when reading SPLIT and SPLIT_END records.
Also Add RecordHeader to represent record having size > 65535.

Bug: 29581559
Change-Id: I0b4556988f77b3431c7f1a28fce65cf225d6a067
Test: run simpleperf_unit_test.
13 files changed