LibJS: Pass Interpreter& to Value::to_number() et al.

This patch is unfortunately rather large and might make some things feel
bloated, but it is necessary to fix a few flaws in LibJS, primarily
blindly coercing values to numbers without exception checks - i.e.

interpreter.argument(0).to_i32();  // can fail!!!

Some examples where the interpreter would actually crash:

var o = { toString: () => { throw Error() } };
+o;
o - 1;
"foo".charAt(o);
"bar".repeat(o);

To fix this, we now have the following...

to_double(Interpreter&)
to_i32()
to_i32(Interpreter&)
to_size_t()
to_size_t(Interpreter&)

...and a whole lot of exception checking.

There's intentionally no to_double(), use as_double() directly instead.

This way we still can use these convenient utility functions but don't
need to check for exceptions if we are sure the value already is a
number.

Fixes #2267.

Libraries/LibJS/Runtime/GlobalObject.cpp

@@ -137,12 +137,18 @@ Value GlobalObject::gc(Interpreter& interpreter)
 
 Value GlobalObject::is_nan(Interpreter& interpreter)
 {
-    return Value(interpreter.argument(0).to_number().is_nan());
+    auto number = interpreter.argument(0).to_number(interpreter);
+    if (interpreter.exception())
+        return {};
+    return Value(number.is_nan());
 }
 
 Value GlobalObject::is_finite(Interpreter& interpreter)
 {
-    return Value(interpreter.argument(0).to_number().is_finite_number());
+    auto number = interpreter.argument(0).to_number(interpreter);
+    if (interpreter.exception())
+        return {};
+    return Value(number.is_finite_number());
 }
 
 Value GlobalObject::parse_float(Interpreter& interpreter)
@@ -151,7 +157,8 @@ Value GlobalObject::parse_float(Interpreter& interpreter)
     if (interpreter.exception())
         return {};
     for (size_t length = string.length(); length > 0; --length) {
-        auto number = Value(js_string(interpreter, string.substring(0, length))).to_number();
+        // This can't throw, so no exception check is fine.
+        auto number = Value(js_string(interpreter, string.substring(0, length))).to_number(interpreter);
         if (!number.is_nan())
             return number;
     }