[jdk8u-dev] RFR: 8221988: add possibility to build with Visual Studio 2019 [v3]

[Alexey Pavlyutkin]

> Hi!
> 
> Please review backport of 8221988. This one opens a bunch of backports enabling support of VS2019. The 11u patch applied with the following changes:
> 
> - changes to absent documentation files skipped
> - resolved baseline conflicts toolchain_windows.m4
> 
> Verification: `bash configure` under VS2019 prompt
> Regression: `bash configure` under VS2017 prompt
> 
> @RealCLanger @mdoerr if you take a look at this I will be very grateful

Alexey Pavlyutkin has updated the pull request incrementally with one additional commit since the last revision:

  rearrange valid VS versions

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

Changes:
  - all: https://git.openjdk.java.net/jdk8u-dev/pull/33/files
  - new: https://git.openjdk.java.net/jdk8u-dev/pull/33/files/f3e81fdb..36e603c1

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk8u-dev&pr=33&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk8u-dev&pr=33&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk8u-dev/pull/33.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk8u-dev pull/33/head:pull/33

PR: https://git.openjdk.java.net/jdk8u-dev/pull/33