JVM IR: Avoid IMPLICIT_NOTNULL checks on special bridge methods

...with dynamic type checks, except for the `@PlatformDependent`
methods, for which the JVM backend adds null checks.

compiler/testData/codegen/box/casts/javaInterop/nullCheckOnMapGetOrDefault.kt

@@ -0,0 +1,27 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// TARGET_BACKEND: JVM
+// JVM_TARGET: 1.8
+// WITH_RUNTIME
+// FULL_JDK
+// FILE: A.java
+public class A {
+    public static A nil() { return null; }
+}
+
+// FILE: test.kt
+fun box(): String {
+    // There is a null check on both arguments of Map.getOrDefault, so we expect this code to throw an exception.
+    // Which exception this is depends on the language version (it's a NullPointerException in Kotlin 1.4).
+    val m = mapOf<A, A>()
+    try {
+        m.getOrDefault(A.nil(), A())
+    } catch (e: Exception) {
+        try {
+            m.getOrDefault(A(), A.nil())
+        } catch (e: Exception) {
+            return "OK"
+        }
+        return "Fail 2"
+    }
+    return "Fail 1"
+}