Or more precisely, when linking with link.exe, but Windows
is our closest proxy for that right now.
This test requires the DWARF info to work, on the Windows on Arm
buildbot it fails:
```
AssertionError: Ran command:
"expr func(1, 2)"
Got output:
error: <user expression 0>:1:1: use of undeclared identifier 'func'
1 | func(1, 2)
| ^~~~
Expecting start string: "error: <user expression 0>:1:1: 'func' has unknown return type" (was not found)
```
Inferred submodule declarations are emitted in DWARF as `DW_TAG_module`s
without `DW_AT_LLVM_include_path`s. Instead the parent DIE will have the
include path. This patch adds support for such setups. Without this, the
`ClangModulesDeclVendor` would fail to `AddModule` the submodules (i.e.,
compile and load the submodules). This would cause errors such as:
```
note: error: Header search couldn't locate module 'TopLevel'
```
The test added here also tests
https://github.com/llvm/llvm-project/pull/141220. Without that patch
we'd fail with:
```
note: error: No module map file in /Users/jonas/Git/llvm-worktrees/llvm-project/lldb/test/API/lang/cpp/decl-from-submodule
```
Unfortunately the embedded clang instance doesn't allow us to use the
decls we find in the modules. But we'll try to fix that in a separate
patch.
rdar://151022173
