[foreign-memaccess+abi] RFR: Add benchmarks to MemorySegmentVsBits [v2]

[Per Minborg]

> This PR proposes the addition of some benchmarks, for example using a LonBuffer and a VarHandle.

Per Minborg has updated the pull request incrementally with one additional commit since the last revision:

  Change to big endian for some variants

-------------

Changes:
  - all: https://git.openjdk.org/panama-foreign/pull/762/files
  - new: https://git.openjdk.org/panama-foreign/pull/762/files/425e0510..e7fc761d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=panama-foreign&pr=762&range=01
 - incr: https://webrevs.openjdk.org/?repo=panama-foreign&pr=762&range=00-01

  Stats: 6 lines in 1 file changed: 0 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/762.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign pull/762/head:pull/762

PR: https://git.openjdk.org/panama-foreign/pull/762