Introduce Char.MIN_VALUE and MAX_VALUE constants (KT-21763)

Add Char.MIN_VALUE and Char.MAX_VALUE implementations in primitive companion objects.
Update builtins test data and public API.

Co-authored-by: Oskar Drozda <themppsplx@gmail.com>

libraries/stdlib/jvm/runtime/kotlin/jvm/internal/PrimitiveCompanionObjects.kt

@@ -51,6 +51,8 @@ internal object ByteCompanionObject {
 
 
 internal object CharCompanionObject {
+    const val MIN_VALUE: Char = '\u0000'
+    const val MAX_VALUE: Char = '\uFFFF'
     const val MIN_HIGH_SURROGATE: Char = '\uD800'
     const val MAX_HIGH_SURROGATE: Char = '\uDBFF'
     const val MIN_LOW_SURROGATE: Char = '\uDC00'