Mark Scanner benchmark as macrobenchmark.

These tests run long enough to be considered macro(as per [1]).
According to [2] it's defined by method's signature.
Also renamed class name as we don't read data from file.

[1] http://cs/android/external/caliper/caliper/src/main/java/com/google/caliper/runner/RuntimeInstrument.java?l=411&rcl=c72541cd245d62653f7dcc56c27a24b106abce95
[2] http://cs/android/external/caliper/caliper/src/main/java/com/google/caliper/runner/BenchmarkMethods.java?l=42&rcl=c033a888bca582b787d2e835c8ba2ad4feb54ec6

Bug: 192640751
Test: vogar --mode device --benchmark \
libcore/benchmarks/src/benchmarks/regression/ScannerBenchmark.java

Change-Id: I7d7fd43296d5870958f5c743540473df9624adec
1 file changed