Revert "[GR-51148] Force javac to silence a ECJ warning in generated code of org.truffleruby"

* This reverts commit fda3b4e.
* Works now.

Author: eregon

mx.truffleruby/suite.py

@@ -287,7 +287,6 @@
             "checkstyle": "org.truffleruby",
             "workingSets": "TruffleRuby",
             "findbugsIgnoresGenerated": True,
-            "forceJavac": True, # GR-51148 We need to force javac to silence a ECJ warning in generated code
             "license": [
                 "EPL-2.0",          # JRuby (we're choosing EPL out of EPL,GPL,LGPL)
                 "BSD-new",          # Rubinius