Add new warning -Wrange-loop-analysis to warn on copies during loops.

Add new warning -Wrange-loop-analysis to warn on copies during loops.

-Wrange-loop-analysis is a subgroup of -Wloop-analysis and will warn when
a range-based for-loop makes copies of the elements in the range.  If possible,
suggest the proper type to prevent copies, or the non-reference to help
distinguish copy versus non-copy forms.  Existing warnings in -Wloop-analysis
are moved to -Wfor-loop-analysis, also a subgroup of -Wloop-analysis.

Differential Revision: http://reviews.llvm.org/D4169

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@234804 91177308-0d34-0410-b5e6-96231b3b80d8