[K/N] Commonize String.regionMatches function

As a part of efforts to stabilize K/N stdlib.

libraries/stdlib/wasm/src/kotlin/text/StringsWasm.kt

@@ -501,6 +501,23 @@ actual fun CharSequence.regionMatches(
     ignoreCase: Boolean
 ): Boolean = regionMatchesImpl(thisOffset, other, otherOffset, length, ignoreCase)
 
+/**
+ * Returns `true` if the specified range in this string is equal to the specified range in another string.
+ * @param thisOffset the start offset in this string of the substring to compare.
+ * @param other the string against a substring of which the comparison is performed.
+ * @param otherOffset the start offset in the other string of the substring to compare.
+ * @param length the length of the substring to compare.
+ */
+@SinceKotlin("1.9")
+@Suppress("ACTUAL_FUNCTION_WITH_DEFAULT_ARGUMENTS")
+public actual fun String.regionMatches(
+    thisOffset: Int,
+    other: String,
+    otherOffset: Int,
+    length: Int,
+    ignoreCase: Boolean = false
+): Boolean = regionMatchesImpl(thisOffset, other, otherOffset, length, ignoreCase)
+
 private val STRING_CASE_INSENSITIVE_ORDER = Comparator<String> { a, b -> a.compareTo(b, ignoreCase = true) }
 
 /**