simpleperf: stat: remove percentage in csv output.

Because percentage isn't correct after we open an event for each cpu.

Bug: 243065368
Bug: 243479304
Test: run simpleperf_unit_test
Change-Id: I67bc23594e82afce040de7755deb9b274b8ad8b8
(cherry picked from commit abc8ee2e0f792d24562405159ae46be19a1c8acb)
1 file changed