[GR-46399] Increase Xmx for Native Image Builder

* The current values are not enough and cause frequent OOM.

Author: eregon

mx.truffleruby/mx_truffleruby.py

@@ -313,13 +313,13 @@ def verify_ci(args):
             jar_distributions=['truffleruby:TRUFFLERUBY-LAUNCHER'],
             main_class='org.truffleruby.launcher.RubyLauncher',
             build_args=[
-                '-J-Xmx5g', # Set Xmx to use a reliable amount of memory
+                '-J-Xmx6g', # Set Xmx to use a reliable amount of memory
                 '-H:+DumpThreadStacksOnSignal',
                 '-H:+DetectUserDirectoriesInImageHeap',
                 '-H:+TruffleCheckBlockListMethods'
             ],
             build_args_enterprise=[
-                '-J-Xmx6g', # Set Xmx to use a reliable amount of memory
+                '-J-Xmx7g', # Set Xmx to use a reliable amount of memory
             ],
             language='ruby',
             option_vars=[