"Main should return Unit" inspection: extend on JUnit test methods

So #KT-24509 Fixed

idea/testData/inspectionsLocal/mainFunctionReturnUnit/junit4Test.kt

@@ -0,0 +1,10 @@
+// PROBLEM: JUnit test should return Unit
+// FIX: Add explicit Unit return type
+// DISABLE-ERRORS
+package org.junit
+
+annotation class Test
+
+class A {
+    @Test fun foo<caret>() = 1
+}

idea/testData/inspectionsLocal/mainFunctionReturnUnit/junit4Test.kt.after

@@ -0,0 +1,10 @@
+// PROBLEM: JUnit test should return Unit
+// FIX: Add explicit Unit return type
+// DISABLE-ERRORS
+package org.junit
+
+annotation class Test
+
+class A {
+    @Test fun foo<caret>(): Unit = 1
+}

idea/testData/inspectionsLocal/mainFunctionReturnUnit/junit5Test.kt

@@ -0,0 +1,9 @@
+// FIX: Add explicit Unit return type
+// DISABLE-ERRORS
+package org.junit.jupiter.api
+
+annotation class Test
+
+class A {
+    @Test fun foo<caret>() = 1
+}

idea/testData/inspectionsLocal/mainFunctionReturnUnit/junit5Test.kt.after

@@ -0,0 +1,9 @@
+// FIX: Add explicit Unit return type
+// DISABLE-ERRORS
+package org.junit.jupiter.api
+
+annotation class Test
+
+class A {
+    @Test fun foo<caret>(): Unit = 1
+}

idea/testData/inspectionsLocal/mainFunctionReturnUnit/notUnit1.kt

@@ -1,3 +1,4 @@
+// PROBLEM: main should return Unit
 // FIX: Add explicit Unit return type
 // DISABLE-ERRORS
 fun <caret>main(args: Array<String>) = 1

idea/testData/inspectionsLocal/mainFunctionReturnUnit/notUnit1.kt.after

@@ -1,3 +1,4 @@
+// PROBLEM: main should return Unit
 // FIX: Add explicit Unit return type
 // DISABLE-ERRORS
 fun main(args: Array<String>): Unit = 1