[jdk11u-ri] RFR: 8210283: Support git as an SCM alternative in the build [v3]

[Erik Joelsson]

> Backport of Git support to 11.0.0.1. Patch applies cleanly after [JDK-8210008](https://bugs.openjdk.org/browse/JDK-8210008).

Erik Joelsson has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' into JDK-8210283-git
 - JDK-8210283
 - JDK-8210008
 - JDK-8303036

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

Changes:
  - all: https://git.openjdk.org/jdk11u-ri/pull/4/files
  - new: https://git.openjdk.org/jdk11u-ri/pull/4/files/e0a32a04..28f79ea1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk11u-ri&pr=4&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk11u-ri&pr=4&range=01-02

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk11u-ri/pull/4.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-ri pull/4/head:pull/4

PR: https://git.openjdk.org/jdk11u-ri/pull/4