Update the Prow presubmit test script to build all targets before running tests.
Update the Prow presubmit test script to build all targets before running tests.

This can catch issues with build targets that aren't used by tests, e.g. binaries.

Change-Id: I8dc46557925a4e3b95e726b7a9e3b70bc43e877a

world-federation-of-advertisers/cross-media-measurement,world-federation-of-advertisers/cross-media-measurement,world-federation-of-advertisers/cross-media-measurement