LibJS: Inline fast case for Value::to_{boolean,number,numeric,primitive}

These functions all have a very common case that can be dealt with a
very simple inline check, often avoiding the need to call an out-of-line
function. This patch moves the common case to inline functions in a new
ValueInlines.h header (necessary due to header dependency issues..)

8% speed-up on the entire Kraken benchmark :^)

Userland/Utilities/js.cpp

@@ -24,6 +24,7 @@
 #include <LibJS/Runtime/GlobalEnvironment.h>
 #include <LibJS/Runtime/JSONObject.h>
 #include <LibJS/Runtime/StringPrototype.h>
+#include <LibJS/Runtime/ValueInlines.h>
 #include <LibJS/SourceTextModule.h>
 #include <LibLine/Editor.h>
 #include <LibMain/Main.h>