Fix debug mac 64 bit build; use far jumps when needed.
Fix debug mac 64 bit build; use far jumps when needed.

This didn't trigger on my machine due to memory layout affecting the size of encoding of immediate constants.

TBR=iposva@google.com

Review URL: https://codereview.chromium.org//844903002

git-svn-id: c93d8a2297af3b929165606efe145742a534bc71@42724 260f80e4-7a28-3924-810f-c04153c831b5

dartino/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dartino/dart-sdk