RFR: 8284588: Remove GensrcCommonLangtools.gmk [v2]

[Magnus Ihse Bursie]

> There's been unnecessary (near) duplication of functionality, and messy logic, in the langtools gensrc step, for a long time. (Basically since we got rid of the mercurial forest...)
> 
> This is a first attempt at cleaning this up. The file GensrcCommonLangtools.gmk is removed. This contained three pieces of functionality. 
> 
> * SetupVersionProperties was moved to GensrcCommonJdk.gmk (which was renamed to GensrcCommon.gmk). 
> * PropertiesParser was only used in one place, and moved there. (jdk.compiler/Gensrc.gmk). It was also heavily rewritten to show more clearly what it actually is doing.
> * SetupCompileProperties (from langtools) were replaced with calls to SetupCompileProperties (from GensrcCommon/"jdk"), which was modified slightly to accomodate for the differences. (Also the Java tool needed to be slightly modified to accept the same syntax as the JDK version of this tool.)
> 
> A reasonable follow-up is to research if the two SetupCompileProperties tools can be unified into one.

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Simplify PARSEPROPERTIES_ARGS

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8167/files
  - new: https://git.openjdk.java.net/jdk/pull/8167/files/11ede464..e84aa180

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8167&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8167&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8167.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8167/head:pull/8167

PR: https://git.openjdk.java.net/jdk/pull/8167