The disassembler impl. of MCDisassembler::getInstruction() was using the pattern

The disassembler impl. of MCDisassembler::getInstruction() was using the pattern
  uint32_t insn;
  MemoryObject.readBytes(Address, 4, (uint8_t*)&insn, NULL)

to read 4 bytes of memory contents into a 32-bit uint variable.  This leaves the
interpretation of byte order up to the host machine and causes PPC test cases of
arm-tests, neon-tests, and thumb-tests to fail.  Fixed to use a byte array for
reading the memory contents and shift the bytes into place for the 32-bit uint
variable in the ARM case and 16-bit halfword in the Thumb case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100403 91177308-0d34-0410-b5e6-96231b3b80d8