Removed for loops in StartImportingBasicBlock() (#3614)
Removed for loops in StartImportingBasicBlock() (#3614)

* Get rid of for loop in StartImportingBasicBlock() and take advantage of EH Indexes on BasicBlock
* Reverted to for loop in StartImportingBasicBlock for try blocks

krytarowski/corert,tijoytom/corert,yizhang82/corert,shrah/corert,gregkalapos/corert,shrah/corert,tijoytom/corert,krytarowski/corert,gregkalapos/corert,krytarowski/corert,gregkalapos/corert,shrah/corert,krytarowski/corert,tijoytom/corert,tijoytom/corert,shrah/corert,gregkalapos/corert,yizhang82/corert,yizhang82/corert,yizhang82/corert