Make Number.Parsing.cs BigEndian friendly (dotnet/coreclr#18853)
Make Number.Parsing.cs BigEndian friendly (dotnet/coreclr#18853)

* Make Number.Parsing.cs BigEndian friendly

* Get rid of DoubleHelper

Signed-off-by: dotnet-bot <03c4cb6107ae99956a7681f2c97ff7104809a2bd@microsoft.com>

ViktorHofer/corefx,shimingsg/corefx,wtgodbe/corefx,ericstj/corefx,ViktorHofer/corefx,ViktorHofer/corefx,ViktorHofer/corefx,ptoonen/corefx,Jiayili1/corefx,wtgodbe/corefx,mmitche/corefx,wtgodbe/corefx,Jiayili1/corefx,ericstj/corefx,ericstj/corefx,Jiayili1/corefx,shimingsg/corefx,BrennanConroy/corefx,shimingsg/corefx,wtgodbe/corefx,mmitche/corefx,ptoonen/corefx,ptoonen/corefx,mmitche/corefx,ViktorHofer/corefx,Jiayili1/corefx,BrennanConroy/corefx,mmitche/corefx,shimingsg/corefx,ptoonen/corefx,Jiayili1/corefx,ptoonen/corefx,shimingsg/corefx,ericstj/corefx,mmitche/corefx,shimingsg/corefx,shimingsg/corefx,mmitche/corefx,Jiayili1/corefx,mmitche/corefx,ericstj/corefx,wtgodbe/corefx,wtgodbe/corefx,Jiayili1/corefx,ericstj/corefx,wtgodbe/corefx,ViktorHofer/corefx,ViktorHofer/corefx,ptoonen/corefx,ptoonen/corefx,ericstj/corefx,BrennanConroy/corefx