[TD] Update diagnostics test data due to new test runners

Update includes:
- Changing syntax of `OI/`NI` tags from `<!NI;TAG!>` to `<!TAG{NI}!>`
- Fix some incorrect directives
- Change order of diagnostics in some places
- Remove ignored diagnostics from FIR test data (previously `DIAGNOSTICS` didn't work)
- Update FIR dumps in some places and add `FIR_IDENTICAL` if needed
- Replace all JAVAC_SKIP with SKIP_JAVAC directive

compiler/testData/diagnostics/tests/controlStructures/when.kt234.kt973.fir.kt

@@ -0,0 +1,41 @@
+//KT-234 Force when() expressions to have an 'else' branch
+//KT-973 Unreachable code
+
+package kt234_kt973
+
+class Pair<A, B>(a: A, b: B)
+
+fun test(t : Pair<Int, Int>) : Int {
+    when (t) {
+        Pair(10, 10) -> return 1
+    }
+    return 0 // unreachable code
+}
+
+fun test1(t : Pair<Int, Int>) : Int {
+    when (t) {
+        Pair(10, 10) -> return 1
+        else -> return 2
+    }
+    return 0 // unreachable code
+}
+
+//more tests
+fun t1(x: Int) = when(x) {
+    else -> 1
+}
+
+fun t5(x: Int) = when (x) {
+    is Int -> 1
+    2 -> 2
+}
+
+fun foo3(x: Int) = when(x) {
+    else -> 1
+    2 -> 2
+}
+
+fun foo4(x: Int) = when(x) {
+    2 -> x
+    else -> 3
+}