[clang-tidy] fix a crash with -fdelayed-template-parsing in UnnecessaryValueParamCheck.
Summary:
This is the same kind of bug than [[ http://reviews.llvm.org/D18238 | D18238 ]].
Fix crashes caused by deferencing null pointer when declarations parsing may be delayed.
The body of the declarations may be null.
The crashes were observed with a Windows build of clang-tidy and the following command-line.
```
command-line switches: -fms-compatibility-version=19 -fms-compatibility
```
Reviewers: alexfh
Subscribers: kimgr, LegalizeAdulthood, cfe-commits
Differential Revision: http://reviews.llvm.org/D18852
git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@265681 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
