RFR: 8364927: Move SmapsParser from runtime/os/TestTracePageSizes.java into testlib

[jonghoonpark]

related jira issue: https://bugs.openjdk.org/browse/JDK-8366716

---

Following the direction outlined in the issue description,
I've extracted the common parts from `TestTracePageSizes` and `TestTransparentHugePagesHeap` to implement the `SmapsParser` test library.

I've confirmed that it works without issues in my local tests.

Reviews and feedback are welcome.

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

Commit messages:
 - Refactor: Introduce SmapsParser

Changes: https://git.openjdk.org/jdk/pull/27273/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27273&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8364927
  Stats: 459 lines in 3 files changed: 234 ins; 212 del; 13 mod
  Patch: https://git.openjdk.org/jdk/pull/27273.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27273/head:pull/27273

PR: https://git.openjdk.org/jdk/pull/27273