WGSL: fix do-while when body has continue If the body of the do while had a "continue" it would skip over the evaluation of the loop condition and potentially loop forever. Change to use the special WGSL "continuing" statement, which goes at the end of a loop body and always executes, even if there is an earlier "continue". Bug: angleproject:42267100 Change-Id: I4ac73e6abcb12e0ff395b83dc5666ac1870724e9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/7003772 Reviewed-by: Liza Burakova <liza@chromium.org> Commit-Queue: Matthew Denton <mpdenton@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>