[NI] Automatically squash equal diagnostics in OI and NI in testdata

compiler/tests-common/tests/org/jetbrains/kotlin/checkers/AbstractDiagnosticsTest.kt

@@ -195,7 +195,7 @@ abstract class AbstractDiagnosticsTest : BaseDiagnosticsTest() {
             exceptionFromDynamicCallDescriptorsValidation = e
         }
 
-        KotlinTestUtils.assertEqualsToFile(getExpectedDiagnosticsFile(testDataFile), actualText.toString()) { s ->
+        KotlinTestUtils.assertEqualsToFile(getExpectedDiagnosticsFile(testDataFile), actualText.cleanupInferenceDiagnostics()) { s ->
             s.replace("COROUTINES_PACKAGE", coroutinesPackage)
         }
 
@@ -211,6 +211,8 @@ abstract class AbstractDiagnosticsTest : BaseDiagnosticsTest() {
         )
     }
 
+    private fun StringBuilder.cleanupInferenceDiagnostics(): String = replace(Regex("NI;([\\S]*), OI;\\1([,!])")) { it.groupValues[1] + it.groupValues[2] }
+
     protected open fun getExpectedDiagnosticsFile(testDataFile: File): File {
         return testDataFile
     }