Update BUILD files to suppress certain errorprone warnings.

Change-Id: I7452d5060eea070fd5dd35a5df6137b89840b5cf
diff --git a/dev/BUILD b/dev/BUILD
index 1154ef2..59389b7 100644
--- a/dev/BUILD
+++ b/dev/BUILD
@@ -128,7 +128,11 @@
     name = "gwt-dev-bare",
     srcs = glob(["core/src/**/*.java"]),
     compatible_with = ["//buildenv/target:appengine"],
-    javacopts = ["-Xep:MissingCasesInEnumSwitch:OFF"],
+    javacopts = [
+        "-Xep:MissingCasesInEnumSwitch:OFF",
+        "-Xep:FallThrough:OFF",
+        "-Xep:ReturnValueIgnored:OFF",
+    ],
     deps = [
         ":compiler.standalone.super",
         "//third_party/java/gson",
@@ -199,7 +203,11 @@
         ],
     ),
     compatible_with = ["//buildenv/target:appengine"],
-    javacopts = ["-Xep:MissingCasesInEnumSwitch:OFF"],
+    javacopts = [
+        "-Xep:MissingCasesInEnumSwitch:OFF",
+        "-Xep:FallThrough:OFF",
+        "-Xep:ReturnValueIgnored:OFF",
+    ],
     deps = [
         ":compiler.standalone.super",
         "//third_party/java/gson",
@@ -295,7 +303,9 @@
         "-Xep:MissingCasesInEnumSwitch:OFF",
         "-Xep:SelfComparison:OFF",
         "-Xep:SelfEquals:OFF",
-    ],
+        "-Xep:FallThrough:OFF",
+        "-Xep:ReturnValueIgnored:OFF",
+   ],
     deps = [
         ":compiler.standalone.super",
         ":gwt-dev-bare",
diff --git a/user/BUILD b/user/BUILD
index a6cb88a..0fdecf9 100644
--- a/user/BUILD
+++ b/user/BUILD
@@ -94,7 +94,13 @@
         ] + JSINTEROP_SRCS,
     ),
     compatible_with = ["//buildenv/target:appengine"],
-    javacopts = ["-Xep:MissingCasesInEnumSwitch:OFF"],
+    javacopts = [
+        "-Xep:MissingCasesInEnumSwitch:OFF",
+        "-Xep:SelfComparison:OFF",
+        "-Xep:SelfEquals:OFF",
+        "-Xep:FallThrough:OFF",
+        "-Xep:ReturnValueIgnored:OFF",
+    ],
     plugins = [
         "//java/com/google/devtools/build/buildjar/plugin/gwt",
     ],
@@ -133,7 +139,13 @@
         "src/com/google/gwt/user/server/Base64Utils.java",
     ],
     compatible_with = ["//buildenv/target:appengine"],
-    javacopts = ["-Xep:MissingCasesInEnumSwitch:OFF"],
+    javacopts = [
+        "-Xep:MissingCasesInEnumSwitch:OFF",
+        "-Xep:SelfComparison:OFF",
+        "-Xep:SelfEquals:OFF",
+        "-Xep:FallThrough:OFF",
+        "-Xep:ReturnValueIgnored:OFF",
+   ],
     deps = [
         "//third_party/java_src/gwt/svn/trunk/dev:requestfactory-apt-deps",
     ],
@@ -532,6 +544,9 @@
         "-Xep:IdentityBinaryExpression:OFF",
         "-Xep:LoopConditionChecker:OFF",
         "-Xep:CollectionIncompatibleType:OFF",
+        "-Xep:MissingCasesInEnumSwitch:OFF",
+        "-Xep:FallThrough:OFF",
+        "-Xep:ReturnValueIgnored:OFF",
     ],
     deps = [
         "//third_party/java/jsr305_annotations",