[ELF] - ICF: test we do not merge sectinons which relocations points to...

[ELF] - ICF: test we do not merge sectinons which relocations points to symbols of the different types.

This test case covers the following line of code:
https://github.com/llvm-mirror/lld/blob/master/ELF/ICF.cpp#L261

Previously it was uncovered.

llvm-svn: 335453