[lldb][windows] fix undeclared identifier error GetModulePath (#180989)

`LLDB_PYTHON_DLL_RELATIVE_PATH` can be unset while
`LLDB_PYTHON_RUNTIME_LIBRARY_FILENAME` is, since it's set automatically
by CMake. This situation causes a build failure which this patch fixes.

This issue was introduced in
https://github.com/llvm/llvm-project/pull/180784.

GitOrigin-RevId: 2fd5479f2c78780c76424d4d918d69b32bf1573c

source/Host/windows/PythonPathSetup/PythonPathSetup.cpp

diff --git a/source/Host/windows/PythonPathSetup/PythonPathSetup.cpp b/source/Host/windows/PythonPathSetup/PythonPathSetup.cpp
index 937977a..b71e10b 100644
--- a/source/Host/windows/PythonPathSetup/PythonPathSetup.cpp
+++ b/source/Host/windows/PythonPathSetup/PythonPathSetup.cpp
@@ -19,7 +19,6 @@
 
 using namespace llvm;
 
-#ifdef LLDB_PYTHON_DLL_RELATIVE_PATH
 static std::string GetModulePath(HMODULE module) {
   std::vector<WCHAR> buffer(MAX_PATH);
   while (buffer.size() <= PATHCCH_MAX_CCH) {
@@ -41,6 +40,7 @@
 /// Returns the full path to the lldb.exe executable.
 static std::string GetPathToExecutable() { return GetModulePath(NULL); }
 
+#ifdef LLDB_PYTHON_DLL_RELATIVE_PATH
 bool AddPythonDLLToSearchPath() {
   std::string path_str = GetPathToExecutable();
   if (path_str.empty())