Do not try to compare two realpaths.

This conservative assert intended to capture future uses of the
shouldPermanentlyIgnore routine and check if we have specified an absolute
non-symlinked path.

Turns out that when we scan for libraries we iterate a given folder which may
move files around. Then the iterable (official) filename's real path might
differ at the point of iteration and the point of the check. Some file systems
use a temporary filename while copying/moving file and the rename it to the
real filename preserving atomicity of the operations.

It looks like this exactly happens in the description of ROOT-10791 -- the
iterator gives the expected real path of the filename which is not yet available
when we ask for the real path of that path we get something different (using the
same inode) eg: `mathsymb.ps` vs `mathsymb.ps_tmp_4810`.

Instead of asserting, let the file system handles this instead.

Kudos to Philippe Canal for investigating this sporadic failure.

lib/Interpreter/DynamicLibraryManagerSymbol.cpp

@@ -687,7 +687,6 @@ namespace cling {
   }
 
   bool Dyld::ShouldPermanentlyIgnore(const std::string& FileName) const {
-    assert(FileName == getRealPath(FileName));
     assert(!m_ExecutableFormat.empty() && "Failed to find the object format!");
 
     if (llvm::sys::fs::is_directory(FileName))