This variable is used to customize different perf script used by
perf-setup under platform_testing/scripts/perf-setup/.
This CL also add perf-setup.sh by default installed for eng and
userdebug build.
Bug: 343133111
Test: . build/envsetup.sh; lunch aosp_akita-trunk_staging-userdebug;\
m perf-setup
Test: . build/envsetup.sh; lunch aosp_panther-trunk_staging-userdebug; \
m perf-setup
Test: . build/envseup.sh; lunch aosp_cf_x86_64_phone-trunk_staging-userdebug; \
m perf-setup
Change-Id: I0f81f5296aa59bef5b5d608a6cfda6d8b05b4e0f
90b90af5f6