Revert "[llvm-objcopy] Fix --section-add when section contain empty bytes"

This reverts commit 0041382198.

The test added is failing on Windows:
  - https://lab.llvm.org/buildbot/#/builders/216/builds/13762
  - https://lab.llvm.org/buildbot/#/builders/123/builds/14447

llvm/lib/ObjCopy/wasm/WasmObjcopy.cpp

@@ -126,11 +126,9 @@ static Error handleArgs(const CommonConfig &Config, Object &Obj) {
     Sec.SectionType = llvm::wasm::WASM_SEC_CUSTOM;
     Sec.Name = NewSection.SectionName;
 
-    llvm::StringRef InputData =
-        llvm::StringRef(NewSection.SectionData->getBufferStart(),
-                        NewSection.SectionData->getBufferSize());
     std::unique_ptr<MemoryBuffer> BufferCopy = MemoryBuffer::getMemBufferCopy(
-        InputData, NewSection.SectionData->getBufferIdentifier());
+        NewSection.SectionData->getBufferStart(),
+        NewSection.SectionData->getBufferIdentifier());
     Sec.Contents = makeArrayRef<uint8_t>(
         reinterpret_cast<const uint8_t *>(BufferCopy->getBufferStart()),
         BufferCopy->getBufferSize());

llvm/test/tools/llvm-objcopy/wasm/add-section.test

@@ -20,17 +20,6 @@
 # REPLACE:   Name:    foo
 # REPLACE:   Payload: 3132330A
 
-# Check that raw data bytes can be imported and exported unchanged especially the ones containing empty bytes.
-# RUN: echo -en '\x02\x01\x00\x01\x02' > %t6
-# RUN: llvm-objcopy --add-section=bar=%t6 %t %t7
-# RUN: llvm-objcopy --dump-section=bar=%t8 %t7
-# RUN: diff %t8 %t6
-# RUN: obj2yaml %t7 | FileCheck %s --check-prefix=RAW-DATA
-
-# Check that raw data is well formated in the file as well.
-# RAW-DATA:      Name: bar
-# RAW-DATA-NEXT: Payload: '0201000102'
-
 --- !WASM
 FileHeader:
   Version: 0x00000001