Bug 537399 - prevent GC on logical type results

Added a bit flag to instruct IAstEvaluationEngine to disable GC on the
result object.

Logical structures use this flag and only reenable GC when the program
resumes.

Change-Id: I0992957be34bad1992f49929c863a252435c4695
Signed-off-by: Julian Honnen <julian.honnen@vector.com>
8 files changed