[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/when/ExhaustiveNullable.fir.kt

@@ -1,3 +1,14 @@
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (POSITIVE)
+ *
+ * SPEC VERSION: 0.1-313
+ * PRIMARY LINKS: expressions, when-expression -> paragraph 5 -> sentence 1
+ * expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 9
+ * expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 10
+ * control--and-data-flow-analysis, performing-analysis-on-the-control-flow-graph, variable-initialization-analysis -> paragraph 2 -> sentence 1
+ * control--and-data-flow-analysis, performing-analysis-on-the-control-flow-graph, variable-initialization-analysis -> paragraph 2 -> sentence 3
+ */
+
 enum class MyEnum {
     A, B
 }
@@ -11,4 +22,4 @@ fun foo(x: MyEnum?): Int {
         null -> y = 0
     }
     return y
-}
+}