[lldb] Restrict TestVariableAnnotationsDisassembler.py to ELF x86_64 (skip on Windows/COFF) (#156026)

The `TestVariableAnnotationsDisassembler.py` test assembles
`d_original_example.s`,
which contains ELF-specific directives such as:

- `.ident`
- `.section ".note.GNU-stack", "", @progbits`
- `.section .debug_line, "", @progbits`

These directives are not understood by COFF on Windows, so the test
fails
on the lldb-remote-linux-win builder even when running on x86_64.

This patch adds a decorator to gate the test,
- `@skipUnlessPlatform(["linux", "freebsd", "netbsd", "android"])` — 
  runs only on ELF platforms

Follow-up to #155942.

Author: UltimateForce21

lldb/test/API/functionalities/disassembler-variables/TestVariableAnnotationsDisassembler.py

@@ -5,6 +5,9 @@
 import re
 
 
+# Requires ELF assembler directives (.section … @progbits, .ident, etc.);
+# not compatible with COFF/Mach-O toolchains.
+@skipUnlessPlatform(["linux", "android", "freebsd", "netbsd"])
 class TestVariableAnnotationsDisassembler(TestBase):
     def _build_obj(self, obj_name: str) -> str:
         # Let the Makefile build all .o’s (pattern rule). Then grab the one we need.