Revert "Wrap clang module files in a Mach-O, ELF, or COFF container."

clang/docs/PCHInternals.rst

clang/include/clang/CodeGen/CodeGenModuleContainer.h

clang/include/clang/Frontend/FrontendActions.h

clang/include/clang/Serialization/ASTReader.h

clang/include/clang/Serialization/ASTWriter.h

clang/lib/CodeGen/CMakeLists.txt

clang/lib/CodeGen/CodeGenModuleContainer.cpp

clang/lib/Frontend/ASTUnit.cpp

clang/lib/Frontend/CMakeLists.txt

clang/lib/Frontend/ChainedIncludesSource.cpp

clang/lib/Frontend/FrontendActions.cpp

clang/lib/Frontend/MultiplexConsumer.cpp

clang/lib/Serialization/ASTReader.cpp

clang/lib/Serialization/CMakeLists.txt

clang/lib/Serialization/GeneratePCH.cpp

clang/lib/Serialization/GlobalModuleIndex.cpp

clang/lib/Serialization/ModuleManager.cpp

clang/test/ARCMT/check-with-pch.m

clang/test/ARCMT/migrate-on-pch-and-module.m

clang/test/ARCMT/objcmt-with-pch.m