[FIR] Fix overloading of renamed jvm methods

#KT-48102 Fixed

compiler/testData/diagnostics/tests/declarationChecks/mappedFunctionNotImplemented.kt

@@ -0,0 +1,13 @@
+// KT-48102
+// FIR_IDENTICAL
+
+// FILE: MyCharSequence.java
+public class MyCharSequence implements CharSequence {
+    public char charAt(int index) { return ' '; }
+    public int length() { return 1; }
+    public CharSequence subSequence(int start, int end) { return this; }
+    public String toString() { return " "; }
+}
+
+// FILE: CharSeq.kt
+class KtCharSeq : MyCharSequence() // false-positive 'get' not implemented