[llvm] [llvm][ELF]Add Shdr check for getBuildID (PR #126537)

[Ruoyu Qiu via llvm-commits]

cabbaken wrote:

> > And I do have 2 questions:
> > ```
> > 1. About the test case about `ShOffset`. How can I make a program header point to a section? I tried setting the same `Offset` and `Vaddr`/`Address`, and that doesn't work. And if there are some documents about `yaml2obj`, please tell me how to find them😢.
> > ```
> 
> The best documentation for yaml2obj is the yaml2obj testsuite, which shows all the different functionality. You can find it at llvm/test/tools/yaml2obj (see the ELF subdirectory for the ELF-format related tests). In this case, you should use [FirstSec/LastSec](https://github.com/llvm/llvm-project/blob/c7dbf20e66606e7e26a28ad567ff75f3a493d3bd/llvm/test/tools/yaml2obj/ELF/program-header.yaml#L30), to force the program header to cover the location of the real section data (those parameters can be the same section, if you only have one section for that program header, as is the case here).

I tried this(actually, I tried this originally):
```
--- !ELF
FileHeader:
  Class:          ELFCLASS64
  Data:           ELFDATA2LSB
  Type:           ET_EXEC
  Machine:        EM_X86_64
ProgramHeaders:
  - Type:         PT_NOTE
    FirstSec:     .note.gnu.build-id
    LastSec:      .note.gnu.build-id
Sections:
  - Name:         .note.gnu.build-id
    Type:         SHT_NOTE
    AddressAlign: 0x04
    ShOffset:     0x8000
    Notes:
      - Name:     "GNU"
        Desc:     "abb50d82b6bdc861"
        Type:     3
```
and the generated ELF's Program Header has an Offset valued `0x8000`(the section data itself is in the file properly), which means it is not pointing to the real section data.

https://github.com/llvm/llvm-project/pull/126537