minor #61103 Fix various bool-type coercions (Girgias)

This PR was squashed before being merged into the 6.4 branch.

Discussion
----------

Fix various bool-type coercions

| Q             | A
| ------------- | ---
| Branch?       | 6.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no <!-- if yes, also update UPGRADE-*.md and src/**/CHANGELOG.md -->
| Issues        |
| License       | MIT

This is cherry-picking some of the commits from #60890 which are basically bugs.
Not sure what the commit naming policy is so do let me know if you want me to manually rebase and rename commits following some guidelines.

Commits
-------

b3d30e3b60e Fix various bool-type coercions

Author: nicolas-grekas

Tests/Constraints/IsbnValidatorTest.php

@@ -121,7 +121,7 @@ public static function getInvalidIsbn()
 
     public function testNullIsValid()
     {
-        $constraint = new Isbn(true);
+        $constraint = new Isbn();
 
         $this->validator->validate(null, $constraint);
 
@@ -130,7 +130,7 @@ public function testNullIsValid()
 
     public function testEmptyStringIsValid()
     {
-        $constraint = new Isbn(true);
+        $constraint = new Isbn();
 
         $this->validator->validate('', $constraint);
 
@@ -140,7 +140,7 @@ public function testEmptyStringIsValid()
     public function testExpectsStringCompatibleType()
     {
         $this->expectException(UnexpectedValueException::class);
-        $constraint = new Isbn(true);
+        $constraint = new Isbn();
 
         $this->validator->validate(new \stdClass(), $constraint);
     }