Support inserting clean calls and other ctis prior to predicated instructions (in IT blocks) in Thumb mode

Created by: zhaoqin

On ARM Thumb code, a cti instrution can only be the last instruction of an IT block, and this makes it tricky to insert a clean call or other cti instructions within an IT block. Currently DynamoRIO automatically reinstates the IT block with instrumented code but did not check if the cti instruction (e.g., the instruction jumps to clean call callee) is the last instruction of the IT block, which makes inserting clean call for a predicated instruction in IT blocks fail.