Revert "[NFC] XFAIL tests which need visibility in XCOFF objectwriting"

[Jake-Egan]

Summary

The tests pass now due to D128148.

This reverts commit 6e8dda047fe0694e113d6571044be154a5059473.

[Jake-Egan]

Already committed here https://github.com/llvm/llvm-project/commit/adc1c34bab8c82e203ebdd04d6d418958e9ccb17

llvm/test/DebugInfo/Generic/pass-by-value.ll

 ; RUN: %llc_dwarf -O0 -filetype=obj < %s | llvm-dwarfdump -debug-info - | FileCheck %s
 ; RUN: %llc_dwarf -O0 -filetype=obj < %s -strict-dwarf=true | llvm-dwarfdump -debug-info - \
 ; RUN:   | FileCheck %s --check-prefix=STRICT --implicit-check-not DW_AT_calling_convention
 ;
-
-; Visibility is unsupported for XCOFF object writing
-; XFAIL: -aix
-
 ; // S is not trivially copyable.
 ; struct S {
 ;    ~S() {}
 ; };
 ;
 ; // T is a POD.
 ; struct T {
 ;    ~T() = default;

llvm/test/DebugInfo/cross-cu-scope.ll

 ; RUN: %llc_dwarf %s -filetype=obj -o %t
 ; RUN: llvm-dwarfdump -debug-info %t | FileCheck %s
 ; REQUIRES: object-emission
 
-; Visibility is unsupported for XCOFF object writing
-; XFAIL: -aix
-
 ; Reduced test case from PR35212. Two DISubprogram belong to a different CU but
 ; share a scope. Both are declarations and end up in the scope's CU. We want to
 ; check that the CU from the context DIE is used (rather than from the IR).
 ; This manifests itself by the DW_base_type ending up in the second CU, rather
 ; than in the first one as specified in the IR.
 
 ; CHECK: DW_TAG_compile_unit
 ; CHECK-NEXT: discriminator 0