Fix multilib test data being installed twice to the same place

Fixes lots of warnings of the form:

build/make/core/base_rules.mk:606: warning: overriding commands for target `out/target/product/generic_arm64/testcases/simpleperf_unit_test/testdata/perf.data'
build/make/core/base_rules.mk:606: warning: ignoring old commands for target `out/target/product/generic_arm64/testcases/simpleperf_unit_test/testdata/perf.data'

Test: lunch aosp_arm64-eng; m device-tests
Change-Id: I32575d25f3aef1d4000fcb63d6ffc025ad21f937