RFR: 8267418: IntelliJ build and test of JavaFX does not work

[Marius Hanl]

Question: I was wondering, should I create a ticket for this as well? Given the fact that I don't have an https://bugs.openjdk.java.net account, I need to use the official bug reporting tool, which looked a bit overkill to me since someone needs to check my created ticket, while this PR is only affecting the IntelliJ IDE with OpenJFX and not the JavaFX platform directly.

This PR fixes the errors you get, when cloning and working with OpenJFX in IntelliJ IDE:
- The **.idea/misc.xml** is modified to use **JDK_11** as language level instead of JDK_8. 
For IntelliJ users: This is the language level shown inside the **Project Structure**. (File -> Project Structure...)
- The **.idea/base.iml, .idea/controls.iml, .idea/fxml.iml, .idea/web.iml, .idea/graphics.iml** are modified to include/recognize JUnit 4. Also the shims are included/recognized (as test resource, this is very similar to the configuration inside the .classpath file from Eclipse)

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Commit messages:
 - Made IntelliJ build working

Changes: https://git.openjdk.java.net/jfx/pull/506/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=506&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267418
  Stats: 62 lines in 6 files changed: 55 ins; 4 del; 3 mod
  Patch: https://git.openjdk.java.net/jfx/pull/506.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/506/head:pull/506

PR: https://git.openjdk.java.net/jfx/pull/506