LibJS/Bytecode: Add Call opcode for fixed-argument-count calls

This avoids the overhead of allocating a new Array on every function
call, saving a substantial amount of time and avoiding GC thrash.

This patch only makes use of Op::Call in CallExpression. There are other
places we should codegen this op. We should also do the same for super
expression calls.

~5% speed-up on Kraken/stanford-crypto-ccm.js

Userland/Libraries/LibJS/Bytecode/Instruction.h

@@ -18,6 +18,7 @@
     O(BitwiseOr)                     \
     O(BitwiseXor)                    \
     O(BlockDeclarationInstantiation) \
+    O(Call)                          \
     O(CallWithArgumentArray)         \
     O(ConcatString)                  \
     O(ContinuePendingUnwind)         \