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/tests/dataClasses/dataClassExplicitlyOverridingCopyNoDefaults.kt

@@ -4,6 +4,6 @@ interface WithCopy<T> {
     fun copy(str: T): WithCopy<T>
 }
 
-<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES_ERROR!>data<!> class <!CONFLICTING_JVM_DECLARATIONS, CONFLICTING_JVM_DECLARATIONS!>Test(val str: String)<!> : WithCopy<String> {
+<!DATA_CLASS_OVERRIDE_DEFAULT_VALUES_ERROR!>data<!> class Test(val str: String) : WithCopy<String> {
     <!CONFLICTING_OVERLOADS!>override fun copy(str: String)<!> = Test(str)
-}
+}