Reapply TargetRegistry refactoring commits.

Reapply TargetRegistry refactoring commits.

--- Reverse-merging r75799 into '.':
 U   test/Analysis/PointerTracking
U    include/llvm/Target/TargetMachineRegistry.h
U    include/llvm/Target/TargetMachine.h
U    include/llvm/Target/TargetRegistry.h
U    include/llvm/Target/TargetSelect.h
U    tools/lto/LTOCodeGenerator.cpp
U    tools/lto/LTOModule.cpp
U    tools/llc/llc.cpp
U    lib/Target/PowerPC/PPCTargetMachine.h
U    lib/Target/PowerPC/AsmPrinter/PPCAsmPrinter.cpp
U    lib/Target/PowerPC/PPCTargetMachine.cpp
U    lib/Target/PowerPC/PPC.h
U    lib/Target/ARM/ARMTargetMachine.cpp
U    lib/Target/ARM/AsmPrinter/ARMAsmPrinter.cpp
U    lib/Target/ARM/ARMTargetMachine.h
U    lib/Target/ARM/ARM.h
U    lib/Target/XCore/XCoreTargetMachine.cpp
U    lib/Target/XCore/XCoreTargetMachine.h
U    lib/Target/PIC16/PIC16TargetMachine.cpp
U    lib/Target/PIC16/PIC16TargetMachine.h
U    lib/Target/Alpha/AsmPrinter/AlphaAsmPrinter.cpp
U    lib/Target/Alpha/AlphaTargetMachine.cpp
U    lib/Target/Alpha/AlphaTargetMachine.h
U    lib/Target/X86/X86TargetMachine.h
U    lib/Target/X86/X86.h
U    lib/Target/X86/AsmPrinter/X86ATTAsmPrinter.h
U    lib/Target/X86/AsmPrinter/X86AsmPrinter.cpp
U    lib/Target/X86/AsmPrinter/X86IntelAsmPrinter.h
U    lib/Target/X86/X86TargetMachine.cpp
U    lib/Target/MSP430/MSP430TargetMachine.cpp
U    lib/Target/MSP430/MSP430TargetMachine.h
U    lib/Target/CppBackend/CPPTargetMachine.h
U    lib/Target/CppBackend/CPPBackend.cpp
U    lib/Target/CBackend/CTargetMachine.h
U    lib/Target/CBackend/CBackend.cpp
U    lib/Target/TargetMachine.cpp
U    lib/Target/IA64/IA64TargetMachine.cpp
U    lib/Target/IA64/AsmPrinter/IA64AsmPrinter.cpp
U    lib/Target/IA64/IA64TargetMachine.h
U    lib/Target/IA64/IA64.h
U    lib/Target/MSIL/MSILWriter.cpp
U    lib/Target/CellSPU/SPUTargetMachine.h
U    lib/Target/CellSPU/SPU.h
U    lib/Target/CellSPU/AsmPrinter/SPUAsmPrinter.cpp
U    lib/Target/CellSPU/SPUTargetMachine.cpp
U    lib/Target/Mips/AsmPrinter/MipsAsmPrinter.cpp
U    lib/Target/Mips/MipsTargetMachine.cpp
U    lib/Target/Mips/MipsTargetMachine.h
U    lib/Target/Mips/Mips.h
U    lib/Target/Sparc/AsmPrinter/SparcAsmPrinter.cpp
U    lib/Target/Sparc/SparcTargetMachine.cpp
U    lib/Target/Sparc/SparcTargetMachine.h
U    lib/ExecutionEngine/JIT/TargetSelect.cpp
U    lib/Support/TargetRegistry.cpp

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75820 91177308-0d34-0410-b5e6-96231b3b80d8