some tests fail on all architectures but amd64

We are running the tests during the Debian package build, but so far we had to ignore the results on all architectures but amd64 since some tests are always failing.
Full build logs including testsuite runs with backtraces for failures are available from https://buildd.debian.org/status/package.php?p=spirv-llvm-translator-15
E.g. on arm64 these 48 tests fail:
```
Failed Tests (48):
LLVM_SPIRV :: DebugInfo/Generic/2009-11-10-CurrentFn.ll
LLVM_SPIRV :: DebugInfo/Generic/2010-03-12-llc-crash.ll
LLVM_SPIRV :: DebugInfo/Generic/2010-03-24-MemberFn.ll
LLVM_SPIRV :: DebugInfo/Generic/2010-10-01-crash.ll
LLVM_SPIRV :: DebugInfo/Generic/PR20038.ll
LLVM_SPIRV :: DebugInfo/Generic/constant-pointers.ll
LLVM_SPIRV :: DebugInfo/Generic/dead-argument-order.ll
LLVM_SPIRV :: DebugInfo/Generic/debug-info-eis-option.ll
LLVM_SPIRV :: DebugInfo/Generic/dwarf-public-names.ll
LLVM_SPIRV :: DebugInfo/Generic/enum.ll
LLVM_SPIRV :: DebugInfo/Generic/func-using-decl.ll
LLVM_SPIRV :: DebugInfo/Generic/global.ll
LLVM_SPIRV :: DebugInfo/Generic/imported-name-inlined.ll
LLVM_SPIRV :: DebugInfo/Generic/inline-scopes.ll
LLVM_SPIRV :: DebugInfo/Generic/inlined-arguments.ll
LLVM_SPIRV :: DebugInfo/Generic/inlined-vars.ll
LLVM_SPIRV :: DebugInfo/Generic/linear-dbg-value.ll
LLVM_SPIRV :: DebugInfo/Generic/linkage-name-abstract.ll
LLVM_SPIRV :: DebugInfo/Generic/member-order.ll
LLVM_SPIRV :: DebugInfo/Generic/missing-abstract-variable.ll
LLVM_SPIRV :: DebugInfo/Generic/multiline.ll
LLVM_SPIRV :: DebugInfo/Generic/namespace_function_definition.ll
LLVM_SPIRV :: DebugInfo/Generic/namespace_inline_function_definition.ll
LLVM_SPIRV :: DebugInfo/Generic/noscopes.ll
LLVM_SPIRV :: DebugInfo/Generic/ptrsize.ll
LLVM_SPIRV :: DebugInfo/Generic/restrict.ll
LLVM_SPIRV :: DebugInfo/Generic/two-cus-from-same-file.ll
LLVM_SPIRV :: DebugInfo/Generic/varargs.ll
LLVM_SPIRV :: DebugInfo/Generic/version.ll
LLVM_SPIRV :: DebugInfo/LocalAddressSpace.ll
LLVM_SPIRV :: DebugInfo/UnknownBaseType.ll
LLVM_SPIRV :: DebugInfo/X86/constant-aggregate.ll
LLVM_SPIRV :: DebugInfo/X86/constant-loclist.ll
LLVM_SPIRV :: DebugInfo/X86/convert-debugloc.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-declare-alloca.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-declare-arg.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-prolog-end.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-value-const-byref.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-value-isel.ll
LLVM_SPIRV :: DebugInfo/X86/dw_op_minus_direct.ll
LLVM_SPIRV :: DebugInfo/X86/dwarf-aranges-no-dwarf-labels.ll
LLVM_SPIRV :: DebugInfo/X86/frame-register.ll
LLVM_SPIRV :: DebugInfo/X86/isel-cse-line.ll
LLVM_SPIRV :: DebugInfo/X86/nophysreg.ll
LLVM_SPIRV :: DebugInfo/X86/partial-constant.ll
LLVM_SPIRV :: DebugInfo/X86/single-dbg_value.ll
LLVM_SPIRV :: DebugInfo/X86/this-stack_value.ll
LLVM_SPIRV :: DebugInfo/expr-opcode.ll

Testing Time: 37.90s
Unsupported : 1
Passed : 589
Expectedly Failed: 5
Failed : 48
```
On ppc64el it's only a subset of 8 failures:
```
Failed Tests (8):
LLVM_SPIRV :: DebugInfo/Generic/missing-abstract-variable.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-declare-alloca.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-declare-arg.ll
LLVM_SPIRV :: DebugInfo/X86/dbg-value-const-byref.ll
LLVM_SPIRV :: DebugInfo/X86/dw_op_minus_direct.ll
LLVM_SPIRV :: DebugInfo/X86/frame-register.ll
LLVM_SPIRV :: DebugInfo/X86/partial-constant.ll
LLVM_SPIRV :: DebugInfo/X86/this-stack_value.ll
```

Start with the Debian build logs linked in the issue and compare the backtraces for the listed LLVM_SPIRV DebugInfo tests on arm64 and ppc64el. Reproduce the architecture-specific failures, beginning with the smaller ppc64el set. Done means the affected tests pass on non-amd64 architectures or the failures have a documented, justified resolution.

Written by the indexing model from the issue text.