[AMDGPU] Don’t marke the .note section as ALLOC

[Flakebi]

Summary

Marking a section as ALLOC tells the ELF loader to load the section into memory.
As we do not want to load the notes into VRAM, the flag should not be there.

[arsenm]

Needs test

[Flakebi]

Fix test, I hope the existing test suffices.

I thought about adding a test that checks that the code section is the only section with flags != 0
but this won’t hold when a data section or others get used.

[nhaehnle]

LGTM

llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUTargetStreamer.cpp

void AMDGPUTargetELFStreamer::EmitNote(
     function_ref<void(MCELFStreamer &)> EmitDesc) {
   auto &S = getStreamer();
   auto &Context = S.getContext();
 
   auto NameSZ = Name.size() + 1;
 
   S.PushSection();
   S.SwitchSection(Context.getELFSection(
-    ElfNote::SectionName, ELF::SHT_NOTE, ELF::SHF_ALLOC));
+    ElfNote::SectionName, ELF::SHT_NOTE, 0));
   S.EmitIntValue(NameSZ, 4);                                  // namesz
   S.EmitValue(DescSZ, 4);                                     // descz
   S.EmitIntValue(NoteType, 4);                                // type
   S.EmitBytes(Name);                                          // name
   S.EmitValueToAlignment(4, 0, 1, 0);                         // padding 0
   EmitDesc(S);                                                // desc
   S.EmitValueToAlignment(4, 0, 1, 0);                         // padding 0
   S.PopSection();