DebugInfo: make test/DebugInfo/X86/debug-macro-dwo.ll more comprehensive

The test doesn't really demonstrate the use of the debug_loc.dwo section
distinct from the debug_loc section for strings in debug_macro.dwo -
because there are no strings that appear uin debug_loc.dwo that weren't
already in debug_loc, so the indexes would remain the same even if the
section that was used was fixed (to use debug_loc.dwo as per spec).

llvm/test/DebugInfo/X86/debug-macro-dwo.ll

@@ -11,10 +11,10 @@
 ; CHECK-NEXT: 0x00000000:
 ; CHECK-NEXT: macro header: version = 0x0005, flags = 0x02, format = DWARF32
 ; CHECK-NEXT: DW_MACRO_start_file - lineno: 0 filenum: 0
-; CHECK-NEXT:   DW_MACRO_start_file - lineno: 1 filenum: 1
+; CHECK-NEXT:   DW_MACRO_start_file - lineno: 1 filenum: 2
 ; CHECK-NEXT:     DW_MACRO_define_strx - lineno: 1 macro: FOO 5
 ; CHECK-NEXT:   DW_MACRO_end_file
-; CHECK-NEXT:   DW_MACRO_start_file - lineno: 2 filenum: 2
+; CHECK-NEXT:   DW_MACRO_start_file - lineno: 2 filenum: 3
 ; CHECK-NEXT:     DW_MACRO_undef_strx - lineno: 14 macro: YEA
 ; CHECK-NEXT:   DW_MACRO_end_file
 ; CHECK-NEXT:   DW_MACRO_undef_strx - lineno: 14 macro: YEA
@@ -29,7 +29,7 @@ target triple = "x86_64-unknown-linux-gnu"
 !llvm.module.flags = !{!14, !15, !16}
 !llvm.ident = !{!17}
 
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 11.0.0", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "test.dwo", emissionKind: FullDebug, enums: !2, macros: !3, splitDebugInlining: false, nameTableKind: None)
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 11.0.0", isOptimized: false, runtimeVersion: 0, splitDebugFilename: "test.dwo", emissionKind: FullDebug, enums: !2, macros: !3, globals: !18, splitDebugInlining: false, nameTableKind: None)
 !1 = !DIFile(filename: "test.c", directory: "/home/", checksumkind: CSK_MD5, checksum: "ef6a7032e0c7ceeef614583f2c00dc80")
 !2 = !{}
 !3 = !{!4}
@@ -47,3 +47,8 @@ target triple = "x86_64-unknown-linux-gnu"
 !15 = !{i32 2, !"Debug Info Version", i32 3}
 !16 = !{i32 1, !"wchar_size", i32 4}
 !17 = !{!"clang version 11.0.0"}
+!18 = !{!19}
+!19 = !DIGlobalVariableExpression(var: !20, expr: !DIExpression())
+!20 = distinct !DIGlobalVariable(name: "i", scope: !0, file: !21, line: 1, type: !22, isLocal: true, isDefinition: true)
+!21 = !DIFile(filename: "./not_used_by_macro.h", directory: "/home/", checksumkind: CSK_MD5, checksum: "cf4b34c263eaaa1d7085c18243b8d101")
+!22 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)