Fix gcc -Wsign-compare warning in X86DisassemblerTables.cpp.

X86_MAX_OPERANDS is changed to unsigned.

Also, add range-based for loops for affected loops. This in turn
needed an ArrayRef instead of a pointer-to-array in
InternalInstruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207413 91177308-0d34-0410-b5e6-96231b3b80d8