JetDiagnosticsTest migrated to TestGenerator

- test data files renamed from *.jet to *.kt

compiler/testData/diagnostics/tests/dataFlowInfoTraversal/Throw.kt

@@ -0,0 +1,9 @@
+fun bar(x: Int): RuntimeException = RuntimeException(x.toString())
+
+fun foo() {
+    val x: Int? = null
+
+    if (x == null) throw bar(<!TYPE_MISMATCH!>x<!>)
+    throw bar(x)
+    throw <!UNREACHABLE_CODE!>bar(x)<!>
+}