RFR: 8271420: Extend CDS custom loader support to Windows platform

[Yumin Qi]

Currently CDS does not support custom loaders on Windows, this patch extends  the support to Windows 64 bit platform.

Tests: mach5 tier1-4

Thanks
Yumin

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Commit messages:
 - Add/Remove conversion between int/size_t for Windows
 - 8271420: CDS should support custom loaders on all platforms

Changes: https://git.openjdk.java.net/jdk/pull/6202/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6202&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8271420
  Stats: 9 lines in 7 files changed: 0 ins; 1 del; 8 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6202.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6202/head:pull/6202

PR: https://git.openjdk.java.net/jdk/pull/6202