Disable programmatic garbage collection for now.

Although this flag allows the build process to be more aggressive about
collecting garbage, it has also been a source of several problems in
Meteor 1.5.2 and Node 4.8.4, from increased segmentation faults during
garbage collection to extreme slowness in rebuilding local packages.

We still use this flag in the Meteor 1.6 betas, where it appears to cause
no problems. For Meteor 1.5.x, however, I think we need to prioritize
development reliability over memory efficiency, for now.

Fixes #8648.
Fixes #9094.

meteor

@@ -133,6 +133,5 @@ fi
 # screw up their meteor installs by have a ~/node_modules
 
 exec "$DEV_BUNDLE/bin/node" \
-     --expose-gc \
      ${TOOL_NODE_FLAGS} \
      "$METEOR" "$@"