Kapt: Provide SourceRetentionAnnotationHandler for incremental compilation.

Collect annotations with the "SOURCE" retention.
(cherry picked from commit 6ef66e7)

plugins/annotation-processing/testData/processors/SourceRetention.kt

@@ -0,0 +1,42 @@
+@Retention(AnnotationRetention.SOURCE)
+annotation class Source1
+
+@Retention(AnnotationRetention.SOURCE)
+annotation class Source2
+
+@Retention(AnnotationRetention.SOURCE)
+annotation class Source3
+
+@Retention(AnnotationRetention.SOURCE)
+annotation class Source4
+
+@Retention(AnnotationRetention.BINARY)
+annotation class Binary
+
+@Retention(AnnotationRetention.RUNTIME)
+annotation class Runtime
+
+@Source1
+class Test
+
+class Test2 {
+    @Source2
+    fun t() {}
+}
+
+class Test3 {
+    @field:Source3
+    val p: String = "A"
+}
+
+class Test4 {
+    fun t(@Source4 a: String) {}
+}
+
+class Test5 {
+    @Retention(AnnotationRetention.SOURCE)
+    annotation class Source5
+
+    @Source5
+    fun t() {}
+}