[FIX] compiler: better handle update of properties with same value

Before this commit, owl would incorrectly skip patching html properties
when the new value is the same as the value used in the previous render.
However, this is incorrect, since the user may have changed the value by
clicking on a checkbox, or changing some text in an input.

So, to be more correct, owl has to force the update whenever it
encounters a prop.  This is however hard to do without impacting the
main update loop, so we kind of work around the problem by using String
and Boolean instance, instead of primitive values.

tests/compiler/attributes.test.ts

@@ -429,6 +429,42 @@ describe("special cases for some specific html attributes/properties", () => {
     expect(input.value).toBe("potato");
   });
 
+  test("input with t-att-value (patching with same value", () => {
+    // render input with initial value
+    const template = `<input t-att-value="v"/>`;
+    const bnode1 = renderToBdom(template, { v: "zucchini" });
+    const fixture = makeTestFixture();
+    mount(bnode1, fixture);
+    const input = fixture.querySelector("input")!;
+    expect(input.value).toBe("zucchini");
+
+    // change value manually in input, to simulate user input
+    input.value = "tomato";
+    expect(input.value).toBe("tomato");
+
+    const bnode2 = renderToBdom(template, { v: "zucchini" });
+    patch(bnode1, bnode2);
+    expect(input.value).toBe("zucchini");
+  });
+
+  test("input, type checkbox, with t-att-checked (patching with same value", () => {
+    // render input with initial value
+    const template = `<input type="checkbox" t-att-checked="v"/>`;
+    const bnode1 = renderToBdom(template, { v: true });
+    const fixture = makeTestFixture();
+    mount(bnode1, fixture);
+    const input = fixture.querySelector("input")!;
+    expect(input.checked).toBe(true);
+
+    // change checked manually in input, to simulate user input
+    input.checked = false;
+    expect(input.checked).toBe(false);
+
+    const bnode2 = renderToBdom(template, { v: true });
+    patch(bnode1, bnode2);
+    expect(input.checked).toBe(true);
+  });
+
   test("input of type checkbox with t-att-indeterminate", () => {
     const template = `<input type="checkbox" t-att-indeterminate="v"/>`;
     const bnode1 = renderToBdom(template, { v: true });