Revert "[lldb] Provide a better error message for missing symbols (#89433)"

This reverts commit 08163cd.

I accidentally broke the test while addressing review feedback.

Author: adrian-prantl

lldb/source/Expression/IRExecutionUnit.cpp

@@ -431,9 +431,7 @@ void IRExecutionUnit::GetRunnableInfo(Status &error, lldb::addr_t &func_addr,
     }
 
     m_failed_lookups.clear();
-    ss.PutCString(
-        "\nHint: The expression tried to call a function that is not present "
-        "in the target, perhaps because it was optimized out by the compiler.");
+
     error.SetErrorString(ss.GetString());
 
     return;

lldb/test/API/lang/cpp/constructors/TestCppConstructors.py

@@ -47,7 +47,7 @@ def test_constructors(self):
         self.expect(
             "expr ClassWithDeletedDefaultCtor().value",
             error=True,
-            substrs=["Couldn't look up symbols:", "function missing"],
+            substrs=["Couldn't look up symbols:"],
         )
 
     @skipIfWindows  # Can't find operator new.