Over the years as more bugs were discovered with the bzip2 library,
new Tests were appended the unit tests and the tests became gnarly.

Clean up the tests to be more consistent with modern Go style in
addition to coalescing common tests into a general version that
iterates over a list of input/output pairs. This has the advantage that
the input, output, and test code are all in the same area, rather than
being sprawled around the test file.

There is no loss of test coverage.

Change-Id: I377ed89378f0b89763d4a56ffc37b22d9c2a369e
Reviewed-on: https://go-review.googlesource.com/20133
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Commit 7a1fb95d50b7a8302445ebc1296010695151ce7b strips non-free license
from Mark.Twain-Tom.Sawyer.txt, but forgot to remove it from the compressed
version of the file.

Update #13216

Change-Id: I60f53275d56ba5baa6898db47b1d41f85e985c00
Reviewed-on: https://go-review.googlesource.com/17264
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Issue 6754 reports that Go bzip2 Decode function is much slower
(about 2.5x in go1.5) than the Python equivalent (which is
actually just a wrapper around the usual C library) on random data.

Profiling the code shows that half a dozen of CMP instructions in a
tight loop are responsibile for most of the execution time.

This patch reduces the number of branches of the loop, greatly
improving performance on random data and speeding up decoding of
real data.

name            old time/op    new time/op    delta
DecodeDigits-4    9.28ms ± 1%    8.05ms ± 1%  -13.18%  (p=0.000 n=15+14)
DecodeTwain-4     28.9ms ± 2%    26.4ms ± 1%   -8.57%  (p=0.000 n=15+14)
DecodeRand-4      3.94ms ± 1%    3.06ms ± 1%  -22.45%  (p=0.000 n=15+14)

name            old speed      new speed      delta
DecodeDigits-4  4.65MB/s ± 1%  5.36MB/s ± 1%  +15.21%  (p=0.000 n=13+14)
DecodeTwain-4   4.32MB/s ± 2%  4.72MB/s ± 1%   +9.36%  (p=0.000 n=15+14)
DecodeRand-4    4.27MB/s ± 1%  5.51MB/s ± 1%  +28.86%  (p=0.000 n=15+14)

I've run some benchmark comparing Go bzip2 implementation with the
usual Linux bzip2 command (which is written in C). On my machine
this patch brings go1.5
  from ~2.26x to ~1.50x of bzip2 time (on 64MB  random data)
  from ~1.70x to ~1.50x of bzip2 time (on 100MB english text)
  from ~2.00x to ~1.88x of bzip2 time (on 64MB  /dev/zero data)

Fixes #6754

Change-Id: I3cb12d2c0c2243c1617edef1edc88f05f91d26d1
Reviewed-on: https://go-review.googlesource.com/13853
Reviewed-by: Nigel Tao <nigeltao@golang.org>

Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.