[docs] Add some memory inspection tips to DebuggingTheCompiler.md.
[docs] Add some memory inspection tips to DebuggingTheCompiler.md.

Add a section about viewing allocation history and reference info about a pointer, and a section about using the lldb `x` command.

parkera/swift,allevato/swift,apple/swift,tkremenek/swift,rudkx/swift,gregomni/swift,stephentyrone/swift,apple/swift,hooman/swift,stephentyrone/swift,tkremenek/swift,allevato/swift,xwu/swift,stephentyrone/swift,airspeedswift/swift,parkera/swift,jmgc/swift,atrick/swift,atrick/swift,stephentyrone/swift,ahoppen/swift,xwu/swift,ahoppen/swift,jckarter/swift,parkera/swift,nathawes/swift,ahoppen/swift,harlanhaskins/swift,apple/swift,tkremenek/swift,jmgc/swift,jmgc/swift,glessard/swift,stephentyrone/swift,roambotics/swift,jckarter/swift,rudkx/swift,ahoppen/swift,roambotics/swift,nathawes/swift,hooman/swift,hooman/swift,gregomni/swift,airspeedswift/swift,glessard/swift,CodaFi/swift,glessard/swift,jmgc/swift,airspeedswift/swift,roambotics/swift,nathawes/swift,CodaFi/swift,harlanhaskins/swift,benlangmuir/swift,atrick/swift,JGiola/swift,gregomni/swift,JGiola/swift,jmgc/swift,JGiola/swift,glessard/swift,JGiola/swift,allevato/swift,allevato/swift,gregomni/swift,gregomni/swift,ahoppen/swift,xwu/swift,CodaFi/swift,nathawes/swift,benlangmuir/swift,tkremenek/swift,jckarter/swift,hooman/swift,xwu/swift,atrick/swift,ahoppen/swift,apple/swift,harlanhaskins/swift,allevato/swift,stephentyrone/swift,gregomni/swift,roambotics/swift,jckarter/swift,parkera/swift,xwu/swift,jckarter/swift,xwu/swift,jckarter/swift,JGiola/swift,rudkx/swift,xwu/swift,apple/swift,jckarter/swift,jmgc/swift,benlangmuir/swift,jmgc/swift,JGiola/swift,benlangmuir/swift,atrick/swift,parkera/swift,airspeedswift/swift,harlanhaskins/swift,roambotics/swift,rudkx/swift,benlangmuir/swift,airspeedswift/swift,nathawes/swift,glessard/swift,apple/swift,allevato/swift,harlanhaskins/swift,tkremenek/swift,hooman/swift,parkera/swift,atrick/swift,airspeedswift/swift,allevato/swift,rudkx/swift,nathawes/swift,stephentyrone/swift,glessard/swift,tkremenek/swift,hooman/swift,hooman/swift,CodaFi/swift,tkremenek/swift,CodaFi/swift,harlanhaskins/swift,benlangmuir/swift,parkera/swift,nathawes/swift,CodaFi/swift,harlanhaskins/swift,CodaFi/swift,rudkx/swift,parkera/swift,airspeedswift/swift,roambotics/swift