SPIRV validation error with global variables

I ran into another issue trying to switch from optimized LLVM IR to using `spirv-opt`:

```llvm
target triple = "spir64-unknown-unknown"
@exception = private unnamed_addr constant [1 x i32] [i32 42]
```

This generates the following SPIRV (as disassembled by `spirv-dis`):

```
; SPIR-V
; Version: 1.0
; Generator: Khronos LLVM/SPIR-V Translator; 14
; Bound: 10
; Schema: 0
OpCapability Addresses
OpCapability Kernel
OpCapability Int64
%1 = OpExtInstImport "OpenCL.std"
OpMemoryModel Physical64 OpenCL
OpSource Unknown 0
OpName %exception "exception"
OpDecorate %exception Constant
%uint = OpTypeInt 32 0
%ulong = OpTypeInt 64 0
%uint_42 = OpConstant %uint 42
%ulong_1 = OpConstant %ulong 1
%_arr_uint_ulong_1 = OpTypeArray %uint %ulong_1
%_ptr_Function__arr_uint_ulong_1 = OpTypePointer Function %_arr_uint_ulong_1
%7 = OpConstantComposite %_arr_uint_ulong_1 %uint_42
%exception = OpVariable %_ptr_Function__arr_uint_ulong_1 Function %7
```

... which fails to validate or optimize:

```
error: line 16: Variables can not have a function[7] storage class outside of a function
%exception = OpVariable %_ptr_Function__arr_uint_ulong_1 Function %7
```

Before, I was optimizing in LLVM and passing the SPIRV binaries generated by `llvm-spirv` directly to the Intel driver, containing the same kind of global variables, without any issue. It's only now that I'm switching to `spirv-opt`, which performs validation, that I'm running into this issue.

Use the provided LLVM IR snippet as the minimal reproducer and inspect the SPIR-V emitted by llvm-spirv, focusing on the global variable's storage class. Run spirv-opt or the SPIR-V validator against the generated module; done means the same input produces SPIR-V that validates and can be optimized without the reported error.

Written by the indexing model from the issue text.