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/Tests/to-number-exception.js

@@ -0,0 +1,38 @@
+load("test-common.js");
+
+try {
+    const message = "oops, Value::to_number() failed";
+    const o = { toString() { throw new Error(message); } };
+
+    assertThrowsError(() => {
+        +o;
+    }, {
+        error: Error,
+        message
+    });
+
+    assertThrowsError(() => {
+        o - 1;
+    }, {
+        error: Error,
+        message
+    });
+
+    assertThrowsError(() => {
+        "foo".charAt(o);
+    }, {
+        error: Error,
+        message
+    });
+
+    assertThrowsError(() => {
+        "bar".repeat(o);
+    }, {
+        error: Error,
+        message
+    });
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}