RFR: 8263236: runtime/os/TestTracePageSizes.java fails on old kernels [v6]

[Aleksey Shipilev]

> See the bug report for details. On some kernels, the madvise hint is not reflected in `/proc/smaps`.
> Rough kernel bisection shows that the hints are reliable since kernel 4.15.
> There are plenty of changes between 4.14.17 and 4.15, none seem obvious as the culprits.
> 
> Additional testing:
>  - [x] Test with kernel 5.4.0 (still passes)
>  - [x] Test with kernel 4.9.0 (used to fail, now passes)
>  - [x] Test with kernel 4.15 (still passes)
>  - [x] Test with kernel 4.14.17 (used to fail, now passes)

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Even simpler patch

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3415/files
  - new: https://git.openjdk.java.net/jdk/pull/3415/files/1df37de7..66f84327

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3415&range=05
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3415&range=04-05

  Stats: 25 lines in 1 file changed: 0 ins; 23 del; 2 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