Add the -Wredundant-move warning.

Dawn uses objects with move semantics like Ref<> that feel like they
need to be std::moved in a bunch of places. This warning triggers when
std::move() is used when it has no effect, keep the code less verbose.

Bug: None
Change-Id: I2b11f709e943e7b16024bfde07910577b983aa34
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/46441
Commit-Queue: Stephen White <senorblanco@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>

src/common/BUILD.gn

@@ -106,6 +106,7 @@ config("dawn_internal") {
       "-Wnon-c-typedef-for-linkage",
       "-Wpessimizing-move",
       "-Wrange-loop-analysis",
+      "-Wredundant-move",
       "-Wshadow-field",
       "-Wstrict-prototypes",
       "-Wtautological-unsigned-zero-compare",