Revert "Bug 572784 - Deploy ecj compiler from 4.20 M1 and use it in Platform"

This reverts commit 799a2058194ddd1c38a56fcafdf70b64e0ab3224.

Reason for revert: Got comparator errors and reverting temporarily Bug 572789

Change-Id: I3389c69e8fd1854337919f39644390dd8442daad
diff --git a/eclipse-platform-parent/pom.xml b/eclipse-platform-parent/pom.xml
index 89f8071..ccb2b6f 100644
--- a/eclipse-platform-parent/pom.xml
+++ b/eclipse-platform-parent/pom.xml
@@ -90,7 +90,7 @@
 
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <cbi-jdt-repo.url>https://repo.eclipse.org/content/repositories/eclipse-staging/</cbi-jdt-repo.url>
-    <cbi-ecj-version>3.26.0.v20210407-0512</cbi-ecj-version>
+    <cbi-ecj-version>3.26.0.v20210317-0507</cbi-ecj-version>
 
     <!--
       Production bundles are produced by ignoring the compiler warnings specified