[LLDB] Do not take address of std::iscntrl in std::remove_if

[KyrBoh]

Summary

Due to the fact, that getting an address of function in the standard library causes undefined behaviour, LLDB fails to compile in my environment with en error saying "unable to find function to call for remove_if(..., <unresolved function type>)".

Just use the fix suggested by cppreference: wrap function into a lambda: https://en.cppreference.com/w/cpp/string/byte/iscntrl

Environment used:
OS: Ubuntu Eoan (19.10), x86_64
Compiler: g++ (Ubuntu 9.2.1-9ubuntu2) 9.2.1 20191008

cmake \
  -DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;libunwind;lldb;compiler-rt;lld;polly" \
  -DLLVM_TARGETS_TO_BUILD="X86" \
  -DLLVM_BUILD_LLVM_DYLIB=ON \
  -DCMAKE_BUILD_TYPE=Release \
  -DCMAKE_INSTALL_PREFIX=/opt/llvm-git \
  ../llvm-project/llvm

[KyrBoh]

Correct patch.

[labath]

I already submitted the very same patch in r375221.

[KyrBoh]

Per labath's comment

lldb/source/Initialization/SystemInitializerCommon.cpp

     }
     if (llvm::Expected<std::string> cwd =
             loader->LoadBuffer<WorkingDirectoryProvider>()) {
-      cwd->erase(std::remove_if(cwd->begin(), cwd->end(), std::iscntrl),
+      cwd->erase(std::remove_if(cwd->begin(), cwd->end(), [](unsigned char c) { return std::iscntrl(c); }),
                  cwd->end());
       if (std::error_code ec = FileSystem::Instance()
                                    .GetVirtualFileSystem()