RFR: 8263236: runtime/os/TestTracePageSizes.java fails on old kernels [v2]

[Aleksey Shipilev]

> See the bug report for details. On some kernels, the madvise hint is not reflected in `/proc/smaps`. Instead, we can use a secondary evidence and read `AnonHugePages`.
> 
> Additional testing:
>  - [x] Test with kernel 5.4.0 (still passes)
>  - [x] Test with kernel 4.9.0 (used to fail, now passes)

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Merge branch 'master' into JDK-8263236-trace-page-sizes
 - Make jcheck happy: remove the TAB
 - 8263236: runtime/os/TestTracePageSizes.java fails on old kernels

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3415/files
  - new: https://git.openjdk.java.net/jdk/pull/3415/files/43271637..6db67d61

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3415&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3415&range=00-01

  Stats: 2637 lines in 54 files changed: 2301 ins; 150 del; 186 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3415.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3415/head:pull/3415

PR: https://git.openjdk.java.net/jdk/pull/3415