LibJS: Add fast path for division of two numbers

We already had fast paths for Add, Sub and Mul. Might as well do Div.

1.18x speed-up on this micro-benchmark:

    (() => {
        let a = 1234;
        for (let i = 0; i < 100_000_000; ++i)
            a / a;
    })()

Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -2003,6 +2003,21 @@ ThrowCompletionOr<void> Mul::execute_impl(Bytecode::Interpreter& interpreter) co
     return {};
 }
 
+ThrowCompletionOr<void> Div::execute_impl(Bytecode::Interpreter& interpreter) const
+{
+    auto& vm = interpreter.vm();
+    auto const lhs = interpreter.get(m_lhs);
+    auto const rhs = interpreter.get(m_rhs);
+
+    if (lhs.is_number() && rhs.is_number()) [[likely]] {
+        interpreter.set(m_dst, Value(lhs.as_double() / rhs.as_double()));
+        return {};
+    }
+
+    interpreter.set(m_dst, TRY(div(vm, lhs, rhs)));
+    return {};
+}
+
 ThrowCompletionOr<void> Sub::execute_impl(Bytecode::Interpreter& interpreter) const
 {
     auto& vm = interpreter.vm();

Libraries/LibJS/Bytecode/Op.h

@@ -113,6 +113,7 @@ private:
     O(BitwiseAnd, bitwise_and)                           \
     O(BitwiseOr, bitwise_or)                             \
     O(BitwiseXor, bitwise_xor)                           \
+    O(Div, div)                                          \
     O(GreaterThan, greater_than)                         \
     O(GreaterThanEquals, greater_than_equals)            \
     O(LeftShift, left_shift)                             \
@@ -124,7 +125,6 @@ private:
     O(UnsignedRightShift, unsigned_right_shift)
 
 #define JS_ENUMERATE_COMMON_BINARY_OPS_WITHOUT_FAST_PATH(O) \
-    O(Div, div)                                             \
     O(Exp, exp)                                             \
     O(Mod, mod)                                             \
     O(In, in)                                               \