Figure out what the fixed expression is, and print it.  Added another target setting to
quietly apply fixits for those who really trust clang's fixits.

Also, moved the retry into ClangUserExpression::Evaluate, where I can make a whole new ClangUserExpression 
to do the work.  Reusing any of the parts of a UserExpression in situ isn't supported at present.

<rdar://problem/25351938>

llvm-svn: 264793
diff --git a/lldb/source/Commands/CommandObjectExpression.h b/lldb/source/Commands/CommandObjectExpression.h
index 4c5bff8..f26ee7a 100644
--- a/lldb/source/Commands/CommandObjectExpression.h
+++ b/lldb/source/Commands/CommandObjectExpression.h
@@ -108,6 +108,7 @@
     CommandOptions m_command_options;
     uint32_t m_expr_line_count;
     std::string m_expr_lines; // Multi-line expression support
+    std::string m_fixed_expression;  // Holds the current expression's fixed text.
 };
 
 } // namespace lldb_private