Change behavior of doubleBuildWithWNoError for Android

"Double build with -Wno-error" is always on in the Android useLlvmNext
wrapper and always off in the production wrapper.  The warnings JSON is
written to $OUT_DIR/warnings_reports.

NFC for the ChromeOS configs.

Originally reviewed in https://android-review.googlesource.com/c/1242126.

BUG=b:149836702
TEST=go test

Change-Id: I5f1a43524772d991b5c64422189643cde61c3826
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2079547
Tested-by: Pirama Arumuga Nainar <pirama@google.com>
Reviewed-by: George Burgess <gbiv@chromium.org>
4 files changed