Enable error level for the JavaLangClash bug pattern in ErrorProne

Fix the current issues so that the build continues to work. This
requires renaming classes that clash with java.lang (in particular
Module, Error and String).

Bug: Issue 15069
Signed-off-by: Edwin Kempin <ekempin@google.com>
Change-Id: I144d5532db0a068eacc2231d89d813d0065abb4b
diff --git a/tools/BUILD b/tools/BUILD
index 36507a9..47a2a2e 100644
--- a/tools/BUILD
+++ b/tools/BUILD
@@ -270,7 +270,7 @@
         "-Xep:JavaDurationWithNanos:ERROR",
         "-Xep:JavaDurationWithSeconds:ERROR",
         "-Xep:JavaInstantGetSecondsGetNano:ERROR",
-        # "-Xep:JavaLangClash:WARN",
+        "-Xep:JavaLangClash:ERROR",
         "-Xep:JavaLocalDateTimeGetNano:ERROR",
         "-Xep:JavaLocalTimeGetNano:ERROR",
         "-Xep:JavaPeriodGetDays:ERROR",