LibJS/Bytecode: Make IdentifierTableIndex a 32-bit index

This makes a bunch of instructions smaller.

Userland/Libraries/LibJS/Bytecode/IdentifierTable.cpp

@@ -11,12 +11,13 @@ namespace JS::Bytecode {
 IdentifierTableIndex IdentifierTable::insert(DeprecatedFlyString string)
 {
     m_identifiers.append(move(string));
-    return m_identifiers.size() - 1;
+    VERIFY(m_identifiers.size() <= NumericLimits<u32>::max());
+    return { static_cast<u32>(m_identifiers.size() - 1) };
 }
 
 DeprecatedFlyString const& IdentifierTable::get(IdentifierTableIndex index) const
 {
-    return m_identifiers[index.value()];
+    return m_identifiers[index.value];
 }
 
 void IdentifierTable::dump() const

Userland/Libraries/LibJS/Bytecode/IdentifierTable.h

@@ -12,7 +12,10 @@
 
 namespace JS::Bytecode {
 
-AK_TYPEDEF_DISTINCT_NUMERIC_GENERAL(size_t, IdentifierTableIndex, Comparison);
+struct IdentifierTableIndex {
+    bool is_valid() const { return value != NumericLimits<u32>::max(); }
+    u32 value { 0 };
+};
 
 class IdentifierTable {
     AK_MAKE_NONMOVABLE(IdentifierTable);

Userland/Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -1758,7 +1758,7 @@ ByteString GetGlobal::to_byte_string_impl(Bytecode::Executable const& executable
 
 ByteString DeleteVariable::to_byte_string_impl(Bytecode::Executable const& executable) const
 {
-    return ByteString::formatted("DeleteVariable {} ({})", m_identifier, executable.identifier_table->get(m_identifier));
+    return ByteString::formatted("DeleteVariable {}", executable.identifier_table->get(m_identifier));
 }
 
 ByteString CreateLexicalEnvironment::to_byte_string_impl(Bytecode::Executable const&) const
@@ -1769,7 +1769,7 @@ ByteString CreateLexicalEnvironment::to_byte_string_impl(Bytecode::Executable co
 ByteString CreateVariable::to_byte_string_impl(Bytecode::Executable const& executable) const
 {
     auto mode_string = m_mode == EnvironmentMode::Lexical ? "Lexical" : "Variable";
-    return ByteString::formatted("CreateVariable env:{} immutable:{} global:{} {} ({})", mode_string, m_is_immutable, m_is_global, m_identifier, executable.identifier_table->get(m_identifier));
+    return ByteString::formatted("CreateVariable env:{} immutable:{} global:{} {}", mode_string, m_is_immutable, m_is_global, executable.identifier_table->get(m_identifier));
 }
 
 ByteString EnterObjectEnvironment::to_byte_string_impl(Executable const& executable) const
@@ -2010,7 +2010,7 @@ ByteString NewClass::to_byte_string_impl(Bytecode::Executable const& executable)
     if (!name.is_empty())
         builder.appendff(", {}", name);
     if (m_lhs_name.has_value())
-        builder.appendff(", lhs_name:{}"sv, m_lhs_name.value());
+        builder.appendff(", lhs_name:{}"sv, executable.get_identifier(m_lhs_name.value()));
     return builder.to_byte_string();
 }