When short-circuiting is necessary (because the right-hand side has side
effects), the following code is generated in SPIR-V:

    // For left && right:
    result = left
    if (left)
        result = right

    // For left || right:
    result = left
    if (!left)
        result = right

Bug: angleproject:4889
Change-Id: Id87b56dc4a1463ed781852a23d2ba6eb2015d700
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2953366
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>