i#1551 port to ARM: add OP_blx client support
i#1551 port to ARM: add OP_blx client support

Extends the OP_blx handling as an indirect call to the client
instrumentation management code.

Review-URL: https://codereview.appspot.com/202110043

AmesianX/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,code4bones/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,daksunt/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,sigma-random/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,AmesianX/dynamorio