IVGCVSW-7510 Delete temporary files created by DebugTestImpl.

* The test cases that use DebugTestImpl were creating temporary files
  but not cleaning them up after running.
* Refactored FileSystem to extract a common RemoveDirectoryAndContents
  function.

Signed-off-by: Colm Donelan <colm.donelan@arm.com>
Change-Id: I35b8d2eeed286742358a9abccbc078493d033902
diff --git a/src/backends/backendsCommon/test/layerTests/DebugTestImpl.cpp b/src/backends/backendsCommon/test/layerTests/DebugTestImpl.cpp
index 2ec94bc..1768f5c 100644
--- a/src/backends/backendsCommon/test/layerTests/DebugTestImpl.cpp
+++ b/src/backends/backendsCommon/test/layerTests/DebugTestImpl.cpp
@@ -79,6 +79,9 @@
 
         armnnUtils::Filesystem::FileContents output = armnnUtils::Filesystem::ReadFileContentsIntoString(full_path);
         CHECK((output == expectedStringOutput));
+
+        // Clean up afterwards.
+        armnnUtils::Filesystem::RemoveDirectoryAndContents(tmpDir);
     }
     else
     {