Change parameterization type in libcore benchmarks.

Junitparams properly reports measurement results with PerfStatusReporter  (unlike Parameterized b/26110951).

Test: atest TestName
Change-Id: I3ac0f368807775f264264947ab913546fc81dbd5
Merged-in: I3ac0f368807775f264264947ab913546fc81dbd5
30 files changed