Disabling assertions fixes some XFAILs on ARMv7

Hi,

This is true for release_34 and trunk. Disabling assertions makes the following tests pass:

Unexpected Passing Tests (5):
LLVM :: ExecutionEngine/2003-05-06-LivenessClobber.ll
LLVM :: ExecutionEngine/2003-08-15-AllocaAssertion.ll
LLVM :: ExecutionEngine/2003-08-23-RegisterAllocatePhysReg.ll
LLVM :: ExecutionEngine/MCJIT/cross-module-sm-pic-a.ll
LLVM :: ExecutionEngine/MCJIT/multi-module-sm-pic-a.ll