LZ4 decompression forward compatibility

[leventov]

This PR adds some forward-compatibility with #4762, not always expecting compressed buffers of the same size. There is no noticeable performance difference:

After
LongCompressionBenchmark.readContinuous  longCompress/   enumerate     longs         lz4  avgt   25  19.520 ± 0.359  ms/op
LongCompressionBenchmark.readContinuous  longCompress/     zipfLow     longs         lz4  avgt   25  35.228 ± 0.709  ms/op
LongCompressionBenchmark.readContinuous  longCompress/    zipfHigh     longs         lz4  avgt   25  22.461 ± 0.316  ms/op
LongCompressionBenchmark.readContinuous  longCompress/  sequential     longs         lz4  avgt   25  60.459 ± 0.938  ms/op
LongCompressionBenchmark.readContinuous  longCompress/     uniform     longs         lz4  avgt   25  33.912 ± 0.465  ms/op
LongCompressionBenchmark.readSkipping    longCompress/   enumerate     longs         lz4  avgt   25   6.340 ± 0.089  ms/op
LongCompressionBenchmark.readSkipping    longCompress/     zipfLow     longs         lz4  avgt   25  22.306 ± 0.423  ms/op
LongCompressionBenchmark.readSkipping    longCompress/    zipfHigh     longs         lz4  avgt   25   9.470 ± 0.126  ms/op
LongCompressionBenchmark.readSkipping    longCompress/  sequential     longs         lz4  avgt   25  47.260 ± 0.726  ms/op
LongCompressionBenchmark.readSkipping    longCompress/     uniform     longs         lz4  avgt   25  20.669 ± 0.366  ms/op

Before
LongCompressionBenchmark.readContinuous  longCompress/   enumerate     longs         lz4  avgt   25  19.553 ± 0.264  ms/op
LongCompressionBenchmark.readContinuous  longCompress/     zipfLow     longs         lz4  avgt   25  34.843 ± 0.463  ms/op
LongCompressionBenchmark.readContinuous  longCompress/    zipfHigh     longs         lz4  avgt   25  22.523 ± 0.293  ms/op
LongCompressionBenchmark.readContinuous  longCompress/  sequential     longs         lz4  avgt   25  59.861 ± 0.673  ms/op
LongCompressionBenchmark.readContinuous  longCompress/     uniform     longs         lz4  avgt   25  34.256 ± 0.548  ms/op
LongCompressionBenchmark.readSkipping    longCompress/   enumerate     longs         lz4  avgt   25   6.414 ± 0.092  ms/op
LongCompressionBenchmark.readSkipping    longCompress/     zipfLow     longs         lz4  avgt   25  21.927 ± 0.518  ms/op
LongCompressionBenchmark.readSkipping    longCompress/    zipfHigh     longs         lz4  avgt   25   9.588 ± 0.142  ms/op
LongCompressionBenchmark.readSkipping    longCompress/  sequential     longs         lz4  avgt   25  46.621 ± 0.667  ms/op
LongCompressionBenchmark.readSkipping    longCompress/     uniform     longs         lz4  avgt   25  20.716 ± 0.305  ms/op

[himanshug]

👍