[foreign-jextract] [Rev 01] RFR: 8237573: Add a basic call overhead benchmark

[Jorn Vernee]

> Hi,
> 
> Per my earlier email [1], this PR adds some basic call overhead benchmarks.
> 
> 2 benchmarks are added:
> - CallOverhead, which measures both an empty and an identity function call.
> - PointsDistance, which extends the existing points benchmarks with one that measures the distance between 2 points doing
>   the calculation is C (using a native call).
> 
> The latter also shows the difference between passing a pointer to a struct, vs passing a struct by value,
> PointsDistance.panama_MemoryAddress and PointsDistance.panama_MemorySegment respectively.
> This acts as a basis to test the coming performance improvements in this area.
> 
> Thanks,
> Jorn
> 
> [1] : https://mail.openjdk.java.net/pipermail/panama-dev/2020-March/008007.html

Jorn Vernee has updated the pull request incrementally with one additional commit since the last revision:

  Fixes to run on Linux

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

Changes:
  - all: https://git.openjdk.java.net/panama-foreign/pull/65/files
  - new: https://git.openjdk.java.net/panama-foreign/pull/65/files/bc4aa3ac..b8b73345

Webrevs:
 - full: https://webrevs.openjdk.java.net/panama-foreign/65/webrev.01
 - incr: https://webrevs.openjdk.java.net/panama-foreign/65/webrev.00-01

  Stats: 3 lines in 2 files changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/panama-foreign/pull/65.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-foreign pull/65/head:pull/65

PR: https://git.openjdk.java.net/panama-foreign/pull/65