LibJS: Optimize source_location_hint and add flag in print_errors

This optimizes the algorithm used in source_location_hint and adds a
flag to not print hints in print_errors.

Userland/Libraries/LibJS/Parser.h

@@ -107,15 +107,26 @@ public:
         {
             if (!position.has_value())
                 return {};
-            // We need to modify the source to match what the lexer considers one line - normalizing
-            // line terminators to \n is easier than splitting using all different LT characters.
-            String source_string { source };
-            source_string.replace("\r\n", "\n");
-            source_string.replace("\r", "\n");
-            source_string.replace(LINE_SEPARATOR, "\n");
-            source_string.replace(PARAGRAPH_SEPARATOR, "\n");
+
             StringBuilder builder;
-            builder.append(source_string.split_view('\n', true)[position.value().line - 1]);
+            String source_string { source };
+            GenericLexer lexer(source_string);
+            // Skip to the line we want
+            size_t current_line = 0;
+            while (current_line < position.value().line - 1) {
+                if (lexer.consume_specific("\n") || lexer.consume_specific("\r\n") || lexer.consume_specific(LINE_SEPARATOR) || lexer.consume_specific(PARAGRAPH_SEPARATOR))
+                    current_line++;
+                else
+                    lexer.ignore();
+                VERIFY(!lexer.is_eof());
+            }
+            // We are at the line, now add the chars to the string
+            while (!lexer.is_eof()) {
+                if (lexer.consume_specific("\n") || lexer.consume_specific("\r\n") || lexer.consume_specific(LINE_SEPARATOR) || lexer.consume_specific(PARAGRAPH_SEPARATOR))
+                    break;
+                else
+                    builder.append(lexer.consume());
+            }
             builder.append('\n');
             for (size_t i = 0; i < position.value().column - 1; ++i)
                 builder.append(spacer);
@@ -126,12 +137,14 @@ public:
 
     bool has_errors() const { return m_state.errors.size(); }
     const Vector<Error>& errors() const { return m_state.errors; }
-    void print_errors() const
+    void print_errors(bool print_hint = true) const
     {
         for (auto& error : m_state.errors) {
-            auto hint = error.source_location_hint(m_state.lexer.source());
-            if (!hint.is_empty())
-                warnln("{}", hint);
+            if (print_hint) {
+                auto hint = error.source_location_hint(m_state.lexer.source());
+                if (!hint.is_empty())
+                    warnln("{}", hint);
+            }
             warnln("SyntaxError: {}", error.to_string());
         }
     }