[CMake] Rename add_compiler_rt_static_runtime to add_compiler_rt_runtime.

Soon there will be an option to build compiler-rt parts as shared libraries
on Linux. Extracted from http://llvm-reviews.chandlerc.com/D3042
by Yuri Gribov.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@205183 91177308-0d34-0410-b5e6-96231b3b80d8