SysInfo::GetUsedCompilerNameAndVer: fix clang version extra quoting
[darwin] SysInfo::GetBuildTargetPlatformVersion: fix OS X minor version decoding, fix OS X 10.10 decoding
[darwin] fix tests for SysInfo::GetKernelName(), add new tests
Merge pull request #4925 from Karlson2k/sysinfo_fix_05

Small darwin fixes for Sysinfo