[cli] Extract target triple setup code into its own method.
[cli] Extract target triple setup code into its own method.

mohtamohit/CppSharp,mono/CppSharp,ddobrev/CppSharp,zillemarco/CppSharp,mono/CppSharp,mono/CppSharp,u255436/CppSharp,u255436/CppSharp,zillemarco/CppSharp,mono/CppSharp,mohtamohit/CppSharp,zillemarco/CppSharp,mohtamohit/CppSharp,mohtamohit/CppSharp,mohtamohit/CppSharp,u255436/CppSharp,mono/CppSharp,zillemarco/CppSharp,ddobrev/CppSharp,u255436/CppSharp,ddobrev/CppSharp,zillemarco/CppSharp,ddobrev/CppSharp,ddobrev/CppSharp,u255436/CppSharp,mono/CppSharp