[FIR] Fix TEST SPEC tests

Ensure the test data contents for both the frontends
are identical. This is needed for proper analysis of
K2-differences.

compiler/tests-spec/testData/diagnostics/linked/control--and-data-flow-analysis/control-flow-graph/expressions-1/conditional-expressions/p-1/neg/1.4.fir.kt

@@ -1,6 +1,15 @@
 // !DIAGNOSTICS: -UNREACHABLE_CODE -IMPLICIT_CAST_TO_ANY -UNUSED_VARIABLE -ASSIGNED_BUT_NEVER_ACCESSED_VARIABLE -UNUSED_VALUE -UNUSED_PARAMETER -UNUSED_EXPRESSION
 // SKIP_TXT
 
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-296
+ * MAIN LINK: control--and-data-flow-analysis, control-flow-graph, expressions-1, conditional-expressions -> paragraph 1 -> sentence 1
+ * NUMBER: 4
+ * DESCRIPTION: check if-expressions must have both branches. (attempt to pass Nothing to if-condition with 'else' key word)
+ */
+
 // TESTCASE NUMBER: 1
 
 fun case1() {