Remove excessive padding from MismatchingNewDeleteDetector

The class MismatchingNewDeleteDetector is in 
lib/Sema/SemaExprCXX.cpp inside the anonymous namespace.
This diff reorders the fields and removes the excessive padding.
Test plan: make -j8 check-clang

Differential revision: https://reviews.llvm.org/D23898


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@280426 91177308-0d34-0410-b5e6-96231b3b80d8