Auto-add pattern for running inner tests in Gradle (KT-24961)

Since Gradle 4.7 there's a more strict pattern check. Simple include
trick doesn't work anymore.

Probably modification of TestSelectionMatcher.java in
https://github.com/gradle/gradle/commit/c2067eaa129af4c9c29ad08da39d1c853eec4c59#diff-e92afe807d7ea74cc9ab0dcef30efc93
is responsible for the new behaviour.

 #KT-24961 Fixed

buildSrc/src/main/kotlin/tasks.kt

@@ -33,11 +33,14 @@ fun Project.projectTest(taskName: String = "test", body: Test.() -> Unit = {}):
         val patterns = filter.includePatterns + ((filter as? DefaultTestFilter)?.commandLineIncludePatterns ?: emptySet())
         if (patterns.isEmpty() || patterns.any { '*' in it }) return@doFirst
         patterns.forEach { pattern ->
+            var isClassPattern = false
             val maybeMethodName = pattern.substringAfterLast('.')
-            val maybeClassFqName = if (maybeMethodName.isFirstChar(::isLowerCase))
+            val maybeClassFqName = if (maybeMethodName.isFirstChar(::isLowerCase)) {
                 pattern.substringBeforeLast('.')
-            else
+            } else {
+                isClassPattern = true
                 pattern
+            }
 
             if (!maybeClassFqName.substringAfterLast('.').isFirstChar(::isUpperCase)) {
                 return@forEach
@@ -46,6 +49,10 @@ fun Project.projectTest(taskName: String = "test", body: Test.() -> Unit = {}):
             val classFileNameWithoutExtension = maybeClassFqName.replace('.', '/')
             val classFileName = "$classFileNameWithoutExtension.class"
 
+            if (isClassPattern) {
+                filter.includePatterns.add("$pattern$*")
+            }
+
             include {
                 val path = it.path
                 if (it.isDirectory) {