[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/smartCasts/varnotnull/prefixNotnullClassIncrement.kt

@@ -1,7 +1,7 @@
 // !WITH_NEW_INFERENCE
 class MyClass
 
-operator fun MyClass.inc(): MyClass { <!OI;UNREACHABLE_CODE!>return<!> null!! }
+operator fun MyClass.inc(): MyClass { <!UNREACHABLE_CODE{OI}!>return<!> null!! }
 
 public fun box() {
     var i : MyClass?
@@ -10,4 +10,4 @@ public fun box() {
     var j = ++<!DEBUG_INFO_SMARTCAST!>i<!>
     // j is null so call is unsafe
     j.hashCode()
-}
+}