RFR: 7301: Add allocation rate aggregators to TLAB Allocation General screen

[Xin Liu]

7301: Add allocation rate aggregators to TLAB Allocation General screen

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Commit messages:
 - add a map from MEMORY to MemoryBandwidth.
 - 7301: Add allocation rate aggregators to TLAB Allocation General screen

Changes: https://git.openjdk.java.net/jmc/pull/391/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=391&range=00
  Issue: https://bugs.openjdk.java.net/browse/JMC-7301
  Stats: 79 lines in 6 files changed: 79 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jmc/pull/391.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/391/head:pull/391

PR: https://git.openjdk.java.net/jmc/pull/391