RFR: 8252600: remove mx configuration [v2]

[Doug Simon]

> This PR updates the configuration files used to develop the JVMCI Java and C++ sources with mx and Eclipse.

Doug Simon has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  8252600: [JVMCI] remove mx configuration

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3559/files
  - new: https://git.openjdk.java.net/jdk/pull/3559/files/7026605f..7c18d2d9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3559&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3559&range=00-01

  Stats: 754 lines in 8 files changed: 0 ins; 754 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3559.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3559/head:pull/3559

PR: https://git.openjdk.java.net/jdk/pull/3559