[vm, gc] Guard PrintStatsToTimeline with SUPPORT_TIMELINE instead of PRODUCT.
[vm, gc] Guard PrintStatsToTimeline with SUPPORT_TIMELINE instead of PRODUCT.

We missed updating this code when SUPPORT_TIMELINE was introduced.

TEST=ci
Change-Id: I534ba9e41063f5381966b4bb0b4af7cb1f80e2b3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/217480
Reviewed-by: Liam Appelbe <78c2029e58e395825ba7228e218c841bb436a9e9@google.com>
Commit-Queue: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk