[clang] [clang][analyzer] Add SyntaxRunningTime per-entry-point metric (PR #163341)

[Arseniy Zaostrovnykh via cfe-commits]

necto wrote:

> LGTM. Have you checked that now the findSummary would get hits when it's using the DefDecl?

I have checked now. in the context of `RunPathSensitiveChecks`  `analysisContext->getDecl()` is equivalent for function decls (but it is different than `getDefinitionOrCanonicalDecl` for some ObjcMethodDecls, and it is more correct), so I will keep it

https://github.com/llvm/llvm-project/pull/163341