[Driver][Fuchsia][NFC] Use GetLinkerPath to see if linker is lld

[phosek]

LGTM

clang/lib/Driver/ToolChains/Fuchsia.cpp

void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   Args.ClaimAllArgs(options::OPT_w);
 
   CmdArgs.push_back("-z");
   CmdArgs.push_back("max-page-size=4096");
 
   CmdArgs.push_back("-z");
   CmdArgs.push_back("now");
 
-  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
-  if (llvm::sys::path::filename(Exec).equals_insensitive("ld.lld") ||
-      llvm::sys::path::stem(Exec).equals_insensitive("ld.lld")) {
+  bool IsLLD;
+  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath(&IsLLD));
+  if (IsLLD) {
     CmdArgs.push_back("-z");
     CmdArgs.push_back("rodynamic");
     CmdArgs.push_back("-z");
     CmdArgs.push_back("separate-loadable-segments");
     CmdArgs.push_back("-z");
     CmdArgs.push_back("rel");
     CmdArgs.push_back("--pack-dyn-relocs=relr");
   }