LibJS: Make ExecutionContext::identifier_table a raw pointer

We were already skipping the bounds checks on this thing anyway,
so might as well shrink ExecutionContext by 8 bytes by doing this.

Author: awesomekling

Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -702,7 +702,7 @@ FLATTEN_ON_CLANG void Interpreter::run_bytecode(size_t entry_point)
 
 Utf16FlyString const& Interpreter::get_identifier(IdentifierTableIndex index) const
 {
-    return m_running_execution_context->identifier_table.data()[index.value];
+    return m_running_execution_context->identifier_table[index.value];
 }
 
 ThrowCompletionOr<Value> Interpreter::run_executable(ExecutionContext& context, Executable& executable, Optional<size_t> entry_point)
@@ -715,7 +715,7 @@ ThrowCompletionOr<Value> Interpreter::run_executable(ExecutionContext& context,
     context.executable = executable;
     context.global_object = realm().global_object();
     context.global_declarative_environment = realm().global_environment().declarative_record();
-    context.identifier_table = executable.identifier_table->identifiers();
+    context.identifier_table = executable.identifier_table->identifiers().data();
 
     ASSERT(executable.registers_and_constants_and_locals_count <= context.registers_and_constants_and_locals_and_arguments_span().size());
 

Libraries/LibJS/Runtime/ExecutionContext.h

@@ -84,7 +84,7 @@ struct JS_API ExecutionContext {
     Optional<size_t> scheduled_jump;
     GC::Ptr<Object> global_object;
     GC::Ptr<DeclarativeEnvironment> global_declarative_environment;
-    ReadonlySpan<Utf16FlyString> identifier_table;
+    Utf16FlyString const* identifier_table { nullptr };
 
     u32 program_counter { 0 };