ARROW-3482: [C++] Build with JEMALLOC by default
ARROW-3482: [C++] Build with JEMALLOC by default

Author: Korn, Uwe <Uwe.Korn@blue-yonder.com>

Closes #2739 from xhochy/ARROW-3482 and squashes the following commits:

8e85cf607 <Korn, Uwe> ARROW-3482:  Build with JEMALLOC by default

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