Tests: do not report backend diagnostics if there's frontend error

In most affected tests, the backend diagnostic such as "conflicting JVM
signature" or "accidental override" is directly caused by some already
existing error reported by frontend, so it doesn't make sense to check
backend diagnostics there.

Tests where that was not the case were moved/copied to
`testsWithJvmBackend`.

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/javaInterop/inheritFromJavaCollectionSubclassWithContainsOverload.fir.kt

@@ -0,0 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER -PARAMETER_NAME_CHANGED_ON_OVERRIDE
+// FILE: A.java
+abstract public class A implements java.util.Collection<String> {
+    public boolean contains(Object x) {return false;}
+    public boolean contains(String x) {return false;}
+}
+
+// FILE: main.kt
+abstract class KA : A() {
+    override fun <!ACCIDENTAL_OVERRIDE_CLASH_BY_JVM_SIGNATURE!>contains<!>(x: String) = false
+}

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/javaInterop/inheritFromJavaCollectionSubclassWithContainsOverload.kt

@@ -0,0 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER -PARAMETER_NAME_CHANGED_ON_OVERRIDE
+// FILE: A.java
+abstract public class A implements java.util.Collection<String> {
+    public boolean contains(Object x) {return false;}
+    public boolean contains(String x) {return false;}
+}
+
+// FILE: main.kt
+abstract class KA : A() {
+    override <!ACCIDENTAL_OVERRIDE!>fun contains(x: String) = false<!>
+}

compiler/testData/diagnostics/testsWithJvmBackend/duplicateJvmSignature/javaInterop/supertypeDifferentParameterNullability.kt

@@ -0,0 +1,18 @@
+// FIR_IDENTICAL
+// FILE: A.java
+import org.jetbrains.annotations.*;
+
+public interface A {
+    void foo(@Nullable String x);
+}
+
+// FILE: B.java
+import org.jetbrains.annotations.*;
+
+public interface B {
+    void foo(@NotNull String x);
+}
+
+// FILE: C.kt
+
+<!CONFLICTING_INHERITED_JVM_DECLARATIONS!>interface I : A, B<!>