K2 JVM: Take JVM declarations conflicting error back

Since SimpleDiagnosticsCollectorWithSuppress have been replaced by
PendingDiagnosticsCollectorWithSuppress after commit 9add6f3d55,
diagnostics need to be committed now.

#KT-54366 Fixed

compiler/testData/cli/jvm/conflictingJvmDeclarations.kt

@@ -0,0 +1,9 @@
+class Foo {
+    val x: Int
+        get() = 42
+
+    fun getX() = 42
+
+    @JvmName("getX")
+    fun getY() = 42
+}