Improve the memory benchmarks by using the JMH framework.

Results:
Benchmark                                          Mode  Cnt        Score      Error  Units
MemoryBenchmark.newClassNode_asm4_0               thrpt    5      196,689 ±  123,711  ops/s
MemoryBenchmark.newClassNode_asm4_0:+memory.used  thrpt    5  2798238,715 ± 3602,377  bytes
MemoryBenchmark.newClassNode_asm5_0               thrpt    5      158,445 ±  111,103  ops/s
MemoryBenchmark.newClassNode_asm5_0:+memory.used  thrpt    5  2693396,799 ± 4985,178  bytes
MemoryBenchmark.newClassNode_asm6_0               thrpt    5      140,053 ±   95,105  ops/s
MemoryBenchmark.newClassNode_asm6_0:+memory.used  thrpt    5  2688716,368 ± 5513,428  bytes
MemoryBenchmark.newClassNode_asm6_1               thrpt    5      165,112 ±   94,423  ops/s
MemoryBenchmark.newClassNode_asm6_1:+memory.used  thrpt    5  2690737,112 ± 4993,252  bytes
MemoryBenchmark.newClass_asm4_0                   thrpt    5      236,938 ±  183,190  ops/s
MemoryBenchmark.newClass_asm4_0:+memory.used      thrpt    5  1823050,423 ± 2051,755  bytes
MemoryBenchmark.newClass_asm5_0                   thrpt    5      266,850 ±    3,303  ops/s
MemoryBenchmark.newClass_asm5_0:+memory.used      thrpt    5  1847376,794 ± 1919,159  bytes
MemoryBenchmark.newClass_asm6_0                   thrpt    5      238,714 ±  197,099  ops/s
MemoryBenchmark.newClass_asm6_0:+memory.used      thrpt    5  1848268,051 ± 2092,874  bytes
MemoryBenchmark.newClass_asm6_1                   thrpt    5      245,291 ±  163,061  ops/s
MemoryBenchmark.newClass_asm6_1:+memory.used      thrpt    5  1844124,244 ± 2064,886  bytes