Change windows cmake to require debug libraries for a debug build, otherwise release libraries

[ted]

Summary

On Windows we require both debug and release python executable/libraries; this change requires debug for a debug build and release for other builds.

If CMAKE_BUILD_TYPE is not specified, the llvm CMakeLists.txt defaults to "Debug".

cmake/modules/LLDBConfig.cmake

     unset(PYTHON_RELEASE_DLL)
   endif()
 
-  if (NOT (PYTHON_DEBUG_EXE AND PYTHON_RELEASE_EXE AND PYTHON_DEBUG_LIB AND PYTHON_RELEASE_LIB AND PYTHON_DEBUG_DLL AND PYTHON_RELEASE_DLL))
-    message("Python installation is corrupt. Python support will be disabled for this build.")
-    set(LLDB_DISABLE_PYTHON 1 PARENT_SCOPE)
-    return()
+  if (CMAKE_BUILD_TYPE STREQUAL "Debug")
+    if (NOT (PYTHON_DEBUG_EXE AND PYTHON_DEBUG_LIB AND PYTHON_DEBUG_DLL))
+      message("Python installation is corrupt. Python support will be disabled for this build.")
+      set(LLDB_DISABLE_PYTHON 1 PARENT_SCOPE)
+      return()
+    endif()
+  else()
+    if (NOT (PYTHON_RELEASE_EXE AND PYTHON_RELEASE_LIB AND PYTHON_RELEASE_DLL))
+      message("Python installation is corrupt. Python support will be disabled for this build.")
+      set(LLDB_DISABLE_PYTHON 1 PARENT_SCOPE)
+      return()
+    endif()
   endif()
 
   # Generator expressions are evaluated in the context of each build configuration generated