The toolchain build scripts are currently defining the tooltool
manifest they use on their own. We move the definitions to the
taskcluster job definitions to normalize on everything using that.
Also use the same cctools as cross-mac builds of Firefox.
Do dummy changes to the corresponding build scripts so that the builds
are force triggered (toolchain builds are not triggered automatically
when the tooltool manifest they use changes yet).
CLOSED TREE
Backed out changeset 158233bce738 (bug 1197325)
Backed out changeset b5ac3fa0bbe7 (bug 1197325)
Backed out changeset 55a8ad127517 (bug 1197325)
