ARROW-3336: [JS] Fix IPC writer serializing sliced Utf8Vectors
ARROW-3336: [JS] Fix IPC writer serializing sliced Utf8Vectors

I just noticed this commit wasn't included in https://github.com/apache/arrow/pull/2638 :-[. My bad, here's the rest of the fix for ARROW-3336

Author: ptaylor <paul.e.taylor@me.com>

Closes #2742 from trxcllnt/js-fix-writing-sliced-arrays and squashes the following commits:

3ab9da080 <ptaylor> fix serializing sliced Utf8 vectors

wesm/arrow,renesugar/arrow,majetideepak/arrow,wesm/arrow,kou/arrow,kou/arrow,itaiin/arrow,xhochy/arrow,cpcloud/arrow,xhochy/arrow,pcmoritz/arrow,kou/arrow,tebeka/arrow,itaiin/arrow,renesugar/arrow,renesugar/arrow,itaiin/arrow,apache/arrow,laurentgo/arrow,cpcloud/arrow,itaiin/arrow,majetideepak/arrow,kou/arrow,renesugar/arrow,kou/arrow,majetideepak/arrow,wesm/arrow,laurentgo/arrow,cpcloud/arrow,xhochy/arrow,xhochy/arrow,wesm/arrow,laurentgo/arrow,tebeka/arrow,cpcloud/arrow,tebeka/arrow,kou/arrow,wesm/arrow,xhochy/arrow,tebeka/arrow,apache/arrow,wesm/arrow,apache/arrow,icexelloss/arrow,majetideepak/arrow,kou/arrow,itaiin/arrow,wesm/arrow,laurentgo/arrow,pcmoritz/arrow,pcmoritz/arrow,apache/arrow,xhochy/arrow,xhochy/arrow,icexelloss/arrow,wesm/arrow,icexelloss/arrow,majetideepak/arrow,laurentgo/arrow,majetideepak/arrow,apache/arrow,renesugar/arrow,laurentgo/arrow,icexelloss/arrow,icexelloss/arrow,icexelloss/arrow,itaiin/arrow,apache/arrow,wesm/arrow,pcmoritz/arrow,kou/arrow,renesugar/arrow,tebeka/arrow,xhochy/arrow,icexelloss/arrow,apache/arrow,renesugar/arrow,xhochy/arrow,renesugar/arrow,itaiin/arrow,itaiin/arrow,cpcloud/arrow,laurentgo/arrow,renesugar/arrow,majetideepak/arrow,renesugar/arrow,itaiin/arrow,itaiin/arrow,xhochy/arrow,laurentgo/arrow,wesm/arrow,cpcloud/arrow,majetideepak/arrow,kou/arrow,laurentgo/arrow,itaiin/arrow,pcmoritz/arrow,icexelloss/arrow,laurentgo/arrow,renesugar/arrow,majetideepak/arrow,pcmoritz/arrow,pcmoritz/arrow,icexelloss/arrow,cpcloud/arrow,laurentgo/arrow,cpcloud/arrow,cpcloud/arrow,renesugar/arrow,wesm/arrow,icexelloss/arrow,cpcloud/arrow,pcmoritz/arrow,majetideepak/arrow,xhochy/arrow,apache/arrow,renesugar/arrow,majetideepak/arrow,cpcloud/arrow,icexelloss/arrow,icexelloss/arrow,laurentgo/arrow,apache/arrow,apache/arrow,cpcloud/arrow,wesm/arrow,kou/arrow,itaiin/arrow,icexelloss/arrow,pcmoritz/arrow,icexelloss/arrow,tebeka/arrow,pcmoritz/arrow,xhochy/arrow,kou/arrow,cpcloud/arrow,apache/arrow,wesm/arrow,majetideepak/arrow,pcmoritz/arrow,kou/arrow,pcmoritz/arrow,tebeka/arrow,apache/arrow,laurentgo/arrow,majetideepak/arrow,majetideepak/arrow,xhochy/arrow,itaiin/arrow,pcmoritz/arrow,apache/arrow,laurentgo/arrow,kou/arrow,laurentgo/arrow,xhochy/arrow,itaiin/arrow,majetideepak/arrow,cpcloud/arrow,pcmoritz/arrow,pcmoritz/arrow,renesugar/arrow,itaiin/arrow,renesugar/arrow,apache/arrow,kou/arrow,wesm/arrow,xhochy/arrow,tebeka/arrow,tebeka/arrow,tebeka/arrow