[llvm] [llvm-objdump][ELF]Fix crash when reading strings from .dynstr(#86612) (PR #125679)

[Ruoyu Qiu via llvm-commits]

================
@@ -470,3 +473,34 @@ Sections:
        Value: 0x1
      - Tag:   DT_NULL
        Value: 0x0
+
+--- !ELF
+FileHeader:
+  Class:   ELFCLASS64
+  Data:    ELFDATA2LSB
+  Type:    ET_EXEC
+  Machine: EM_X86_64
+Sections:
+  - Name:    .dynstr
+    Type:    SHT_STRTAB
+    Address: 0x1000
+    Size:    0x10
+    Content: "004400550066007700"
+  - Name: .dynamic
+    Type: SHT_DYNAMIC
+    Entries:
+     - Tag:   DT_NEEDED
+       Value: 0x1245657656
----------------
cabbaken wrote:

I thought the edge of the value may depend on the the OS or the hardware.
Since this value is the offset of the .dynstr(we need this value to be exceed max virtual address), it may have different edge value in different architecture and OS.
Please let me know if this interpretation is off or if there are additional considerations to be aware of, and thanks for your review~

https://github.com/llvm/llvm-project/pull/125679