Merging r242919:

Merging r242919:
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r242919 | rengolin | 2015-07-22 11:21:39 -0700 (Wed, 22 Jul 2015) | 8 lines

[Release] Allow release testers to disable certain components

Not all components build correctly on all targets and the release
script had no way to disable them other than editing the script locally.

This change provides a way to disable the test-suite, compiler-rt and
the libraries, as well as allowing you to re-run on the same directory
without checking out all sources again.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_37@242937 91177308-0d34-0410-b5e6-96231b3b80d8