Deprecate Char-to-Number conversions in stdlib (Native)

- Synchronize code of Ranges, Progressions, ProgressionIterators
- Suppress deprecations in regex implementation code

KT-23451

kotlin-native/backend.native/tests/stdlib_external/text/StringNativeTest.kt

@@ -56,7 +56,7 @@ class StringNativeTest {
             }
 
             fun Char.hex(): String {
-                return toInt().toString(16).padStart(4, '0')
+                return code.toString(16).padStart(4, '0')
             }
 
             val sigma = '\u03A3'