[lldb] Mark operator== const to avoid ambiguity in C++20. (#68224)

C++20 will automatically generate an operator== with reversed operand
order, which is ambiguous with the written operator== when one argument
is marked const and the other isn't.

These operators currently trigger -Wambiguous-reversed-operator at usage
sites lldb/source/Symbol/SymbolFileOnDemand.cpp:68 and
lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp:1286.

Author: bazuzi

lldb/include/lldb/Utility/XcodeSDK.h

@@ -69,7 +69,7 @@ class XcodeSDK {
 
   XcodeSDK &operator=(const XcodeSDK &other);
   XcodeSDK(const XcodeSDK&) = default;
-  bool operator==(const XcodeSDK &other);
+  bool operator==(const XcodeSDK &other) const;
 
   /// Return parsed SDK type and version number.
   Info Parse() const;

lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp

@@ -606,8 +606,8 @@ void DynamicLoaderDarwinKernel::KextImageInfo::SetProcessStopId(
   m_load_process_stop_id = stop_id;
 }
 
-bool DynamicLoaderDarwinKernel::KextImageInfo::
-operator==(const KextImageInfo &rhs) {
+bool DynamicLoaderDarwinKernel::KextImageInfo::operator==(
+    const KextImageInfo &rhs) const {
   if (m_uuid.IsValid() || rhs.GetUUID().IsValid()) {
     return m_uuid == rhs.GetUUID();
   }

lldb/source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.h

@@ -176,7 +176,7 @@ class DynamicLoaderDarwinKernel : public lldb_private::DynamicLoader {
 
     void SetProcessStopId(uint32_t stop_id);
 
-    bool operator==(const KextImageInfo &rhs);
+    bool operator==(const KextImageInfo &rhs) const;
 
     uint32_t GetAddressByteSize(); // as determined by Mach-O header
 

lldb/source/Utility/XcodeSDK.cpp

@@ -56,7 +56,7 @@ XcodeSDK::XcodeSDK(XcodeSDK::Info info) : m_name(GetName(info.type).str()) {
 
 XcodeSDK &XcodeSDK::operator=(const XcodeSDK &other) = default;
 
-bool XcodeSDK::operator==(const XcodeSDK &other) {
+bool XcodeSDK::operator==(const XcodeSDK &other) const {
   return m_name == other.m_name;
 }