[vm] Fix -Werror=format-overflow when building with gcc.
[vm] Fix -Werror=format-overflow when building with gcc.

TEST=ci
Change-Id: I9bb9d2658ab81322a07ee2892ddc9ac82332424e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/256024
Commit-Queue: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>
Reviewed-by: Alexander Aprelev <dfb74c35a357c2059971a4bf7fe26b6a7c18085d@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