RFR: 8290373: Enable lossy conversion warnings on Windows

[Jorn Vernee]

This patch enables lossy conversion warnings (C4244 [1]) for hotspot on Windows/MSVC. Instead of fixing all warnings that were produced from this, I've instead locally disabled the warning in the files that produced warnings. This allows gradually making progress with cleaning up these warnings on a per-file basis, instead of trying to fix all of them in one shot.

Out of the ~1100 files that make up hotspot on Windows x64, ~290 have warnings for them disabled (not counting aarch64 files), which means that with this patch ~800 files are protected by enabling this warning globally.

Warnings can be fixed in individual files, or groups of files in followup patches, and warnings for those files can be enabled.

I'm working on a patch that does the same for GCC, but it produces warnings in about 150 more files (mostly linux/posix specific files), so I wanted to gather feedback on this approach before continuing with that.

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To disable warnings for a file, in most cases the following prelude is added after the last `#include` at the start of a file:

    PRAGMA_DIAG_PUSH
    PRAGMA_ALLOW_LOSSY_CONVERSIONS

And then the following is added at the end of the file for cpp files, or before closing the header guard for hpp files:

    PRAGMA_DIAG_POP

1 notable exception are files produced by adlc, which had their code-gen modified to add these lines instead. There were also 2 files that include headers in the middle of the file (ostream.cpp & sharedRuntime.cpp), for which I've added the PRAGMA's after the include block at the start of the file instead. They only included system headers, for which disabling warnings doesn't matter any ways.

[1]: https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-levels-3-and-4-c4244?view=msvc-170

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Commit messages:
 - Rest of the tests
 - More test
 - AArch64
 - Disable for tests
 - Fix apostrophe
 - Last few manual
 - Automatics
 - WIP
 - More disabled warnings
 - Enable narrow conversion warnings

Changes: https://git.openjdk.org/jdk/pull/9516/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9516&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290373
  Stats: 1586 lines in 318 files changed: 1579 ins; 3 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/9516.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9516/head:pull/9516

PR: https://git.openjdk.org/jdk/pull/9516