JIT: enable GDV when static class deduction fails.

Update the early bailout in impDevirtualizeCall that gives up if
the object class cannot not be determined to check if we can do
GDV (guarded devirtualization) based on profile data.

Fixes one of the cases noted in #55079.

src/coreclr/jit/importer.cpp

@@ -20935,25 +20935,37 @@ void Compiler::impDevirtualizeCall(GenTreeCall*            call,
         return;
     }
 
+    // Fetch information about the class that introduced the virtual method.
+    CORINFO_CLASS_HANDLE baseClass        = info.compCompHnd->getMethodClass(baseMethod);
+    const DWORD          baseClassAttribs = info.compCompHnd->getClassAttribs(baseClass);
+
+    // Is the call an interface call?
+    const bool isInterface = (baseClassAttribs & CORINFO_FLG_INTERFACE) != 0;
+
     // See what we know about the type of 'this' in the call.
     GenTree*             thisObj      = call->gtCallThisArg->GetNode()->gtEffectiveVal(false);
     bool                 isExact      = false;
     bool                 objIsNonNull = false;
     CORINFO_CLASS_HANDLE objClass     = gtGetClassHandle(thisObj, &isExact, &objIsNonNull);
 
     // Bail if we know nothing.
-    if (objClass == nullptr)
+    if (objClass == NO_CLASS_HANDLE)
     {
         JITDUMP("\nimpDevirtualizeCall: no type available (op=%s)\n", GenTree::OpName(thisObj->OperGet()));
-        return;
-    }
 
-    // Fetch information about the class that introduced the virtual method.
-    CORINFO_CLASS_HANDLE baseClass        = info.compCompHnd->getMethodClass(baseMethod);
-    const DWORD          baseClassAttribs = info.compCompHnd->getClassAttribs(baseClass);
+        // Don't try guarded devirtualiztion when we're doing late devirtualization.
+        //
+        if (isLateDevirtualization)
+        {
+            JITDUMP("No guarded devirt during late devirtualization\n");
+            return;
+        }
 
-    // Is the call an interface call?
-    const bool isInterface = (baseClassAttribs & CORINFO_FLG_INTERFACE) != 0;
+        considerGuardedDevirtualization(call, ilOffset, isInterface, baseMethod, baseClass,
+                                        pContextHandle DEBUGARG(objClass) DEBUGARG("unknown"));
+
+        return;
+    }
 
     // If the objClass is sealed (final), then we may be able to devirtualize.
     const DWORD objClassAttribs = info.compCompHnd->getClassAttribs(objClass);