Revert "[offload][SYCL] Add SYCL Module splitting (#119713)"

This reverts commit bfeea10.

Author: jhuber6

llvm/include/llvm/Transforms/Utils/SYCLSplitModule.h

@@ -83,8 +83,6 @@ add_llvm_component_library(LLVMTransformUtils
   SizeOpts.cpp
   SplitModule.cpp
   StripNonLineTableDebugInfo.cpp
-  SYCLSplitModule.cpp
-  SYCLUtils.cpp
   SymbolRewriter.cpp
   UnifyFunctionExitNodes.cpp
   UnifyLoopExits.cpp