[OPCODE][AARCH64]Check mapping symbol while backward searching for IT block

[Nick Clifton]

Hi Renlin,

> The related patch searches for proper mapping symbols. They are defined in arm elf document.
> So the test case should be limited on elf target only. I will post a fix.

Oops - sorry - I have only just seen this.  Please feel free to revert my patch to skip the test for PE targets.  (I really should finish reading my email before running the regressions tests...)

Cheers
   Nick