[8u] RFR 8221408: Windows 32bit build build errors/warnings in hotspot

[Zhengyu Gu]

I would like to backport this patch to 8u for parity with Oracle 8u281.

The backport is based on 11u patch and it does not apply cleanly.

1) classFileParser.cpp: change already in 8u via JDK-8205677
2) os_windows_x86.cpp: context is slightly different

The original bug: https://bugs.openjdk.java.net/browse/JDK-8221408
11u patch: https://hg.openjdk.java.net/jdk-updates/jdk11u/rev/f03e922bfcb8

8u webrev: http://cr.openjdk.java.net/~zgu/JDK-8221408-8u/webrev.00/

Test:
   Built 32-bit JDKs on Windows (release and fastdebug)

Thanks,

-Zhengyu