Add a clang-tidy check that flags string-to-number conversion functions that...

Add a clang-tidy check that flags string-to-number conversion functions that have insufficient error checking, suggesting a better alternative.

This check corresponds to: https://www.securecoding.cert.org/confluence/display/c/ERR34-C.+Detect+errors+when+converting+a+string+to+a+number

llvm-svn: 268100