[VM] Fix crash on >num filter in heapsnapshot tool

Change-Id: I873d98452e88d2b55b485cc14daa1823af2ba0f2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/273741
Commit-Queue: Jens Johansen <[email protected]>
Reviewed-by: Martin Kustermann <[email protected]>

Author: jensjoha

runtime/tools/heapsnapshot/lib/src/expression.dart

@@ -84,7 +84,7 @@ class DFilterExpression extends SetExpression {
             final len = analysis.variableLengthOf(o);
             return len != -1 && len >= limit;
           };
-        if (ge)
+        if (g)
           return (o) {
             final len = analysis.variableLengthOf(o);
             return len != -1 && len > limit;