Reduce number of iterations for Level-1 benchmarks

Because of the larger input and reduced jitter, we don't need as much
warmup and measurements.

Author: luhenry

benchmarks/src/main/java/dev/ludovic/netlib/benchmarks/blas/l1/L1Benchmark.java

@@ -29,7 +29,7 @@
 
 import org.openjdk.jmh.annotations.*;
 
-@Warmup(iterations = 6)
-@Measurement(iterations = 12)
+@Warmup(iterations = 3)
+@Measurement(iterations = 6)
 public class L1Benchmark extends BLASBenchmark {
 }