Enable new exception handling by default (#98570)

* Enable new exception handling by default

This change just flips the config knob to enable the new exception
handling by default.

* Add runtime.config setting for enabling the new EH

* Reflect PR - switch the config name

From the EnableNewExceptionHandling to LegacyExceptionHandling

Author: janvorli

src/coreclr/inc/clrconfigvalues.h

@@ -259,7 +259,7 @@ RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_legacyCorruptedStateExceptionsPolicy, W("le
 CONFIG_DWORD_INFO(INTERNAL_SuppressLostExceptionTypeAssert, W("SuppressLostExceptionTypeAssert"), 0, "")
 RETAIL_CONFIG_DWORD_INFO(INTERNAL_UseEntryPointFilter, W("UseEntryPointFilter"), 0, "")
 RETAIL_CONFIG_DWORD_INFO(INTERNAL_Corhost_Swallow_Uncaught_Exceptions, W("Corhost_Swallow_Uncaught_Exceptions"), 0, "")
-RETAIL_CONFIG_DWORD_INFO(EXTERNAL_EnableNewExceptionHandling, W("EnableNewExceptionHandling"), 0, "Enable new exception handling.");
+RETAIL_CONFIG_DWORD_INFO(EXTERNAL_LegacyExceptionHandling, W("LegacyExceptionHandling"), 0, "Enable legacy exception handling.");
 
 
 ///

src/coreclr/vm/exceptionhandling.cpp

@@ -19,6 +19,7 @@
 #include "corinfo.h"
 #include "exceptionhandlingqcalls.h"
 #include "exinfo.h"
+#include "configuration.h"
 
 #if defined(TARGET_X86)
 #define USE_CURRENT_CONTEXT_IN_FILTER
@@ -236,7 +237,7 @@ void InitializeExceptionHandling()
     // Initialize the lock used for synchronizing access to the stacktrace in the exception object
     g_StackTraceArrayLock.Init(LOCK_TYPE_DEFAULT, TRUE);
 
-    g_isNewExceptionHandlingEnabled = CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_EnableNewExceptionHandling) != 0;
+    g_isNewExceptionHandlingEnabled = Configuration::GetKnobBooleanValue(W("System.Runtime.LegacyExceptionHandling"), CLRConfig::EXTERNAL_LegacyExceptionHandling ) == 0;
 
 #ifdef TARGET_UNIX
     // Register handler of hardware exceptions like null reference in PAL