RFR: 8299592: Fix and reenable warnings in java.desktop native code compilation [v4]

[Daniel Jeliński]

> Please review this patch that fixes and re-enables a few warnings in libawt compilation.
> 
> Verified that debug and release builds finish successfully on Win, Mac and Linux. Also verified that client libs tests still pass.

Daniel Jeliński has updated the pull request incrementally with one additional commit since the last revision:

  Align type names

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11841/files
  - new: https://git.openjdk.org/jdk/pull/11841/files/54cd307d..35413909

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11841&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11841&range=02-03

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11841.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/11841/head:pull/11841

PR: https://git.openjdk.org/jdk/pull/11841