simpleperf: update test to use ExampleCpp.

1. Replace ExampleWithNative with ExampleCpp in tests.
2. Fix TestExampleCpp.test_annotate, which is broken because
llvm-symbolizer may output empty function name. So fix Addr2NearestLine
code parsing llvm-symbolizer output.
3. Some cpp tests have reason to fail on selected Android versions on
x86. So add code to skip them.

Bug: 203246914
Test: run scripts/test/test.py -p TestExampleCpp* on Android N-S

Change-Id: Ia39a7e9068ac58d3912473219bd19b98e72595bc
4 files changed