[lldb][Windows] Fix build with MSVC compiler broken by (llvm#108072)

This patch fixes LLDB Windows build with MSVC compiler. MSVC deletes
the default constructor due to virtual inheritance rules. Explicitly
define the default constructor in NativeRegisterContextWindows to
ensure constructibility.

Author: omjavaid

lldb/source/Plugins/Process/Windows/Common/NativeRegisterContextWindows.h

@@ -24,6 +24,10 @@ class NativeRegisterContextWindows
   CreateHostNativeRegisterContextWindows(const ArchSpec &target_arch,
                                          NativeThreadProtocol &native_thread);
 
+  // MSVC compiler deletes the default constructor due to virtual inheritance.
+  // Explicitly defining it ensures the class remains constructible.
+  NativeRegisterContextWindows() {}
+
 protected:
   lldb::thread_t GetThreadHandle() const;
 };