Replace Java 11 API usage with Java 8 equivalent.

This CL replaces Java 11's InputStream.transferTo with the Java 8
equivalent. This is currently needed for Dagger, which is built with
Java 8 in open source.

Test: ./room/gradlew -p room :room:r-c-p:test
Change-Id: Ib50aac7bbef50d3cee41e0578853c0c74244d582
diff --git a/room/room-compiler-processing-testing/src/main/java/androidx/room/compiler/processing/util/compiler/steps/JavaSourceCompilationStep.kt b/room/room-compiler-processing-testing/src/main/java/androidx/room/compiler/processing/util/compiler/steps/JavaSourceCompilationStep.kt
index 27b3e95..57185d2 100644
--- a/room/room-compiler-processing-testing/src/main/java/androidx/room/compiler/processing/util/compiler/steps/JavaSourceCompilationStep.kt
+++ b/room/room-compiler-processing-testing/src/main/java/androidx/room/compiler/processing/util/compiler/steps/JavaSourceCompilationStep.kt
@@ -68,7 +68,7 @@
                 }
                 it.openInputStream().use { inputStream ->
                     targetFile.outputStream().use { outputStream ->
-                        inputStream.transferTo(outputStream)
+                        inputStream.copyTo(outputStream)
                     }
                 }
             }