StringBuilder::AppendFormatHelper is not compiled

[tarekgh]

run the code:
Console.WriteLine("{0}", "Hi");

will get the following stack:
#0 0x00007ffff6c01cc9 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007ffff6c050d8 in __GI_abort () at abort.c:89
#2 0x00007ffff7b36535 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#3 0x00007ffff7b346d6 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#4 0x00007ffff7b34703 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#5 0x00007ffff7b34922 in __cxa_throw () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6
#6 0x00000000004104b3 in System_Private_CoreLib::System::Text::StringBuilder::AppendFormatHelper (_this=0x7fffdebcdfb0, provider=0x7fffdebcb9e0, format=0x7fffdebcdef8, args=...)

at obj/Debug/dnxcore50/native/Hello.cpp:22781

#7 0x000000000041017d in System_Private_CoreLib::System::String::FormatHelper (provider=0x7fffdebcb9e0, format=0x7fffdebcdef8, args=...) at obj/Debug/dnxcore50/native/Hello.cpp:8824
#8 0x00000000004131ab in System_Private_CoreLib::System::String::Format_5 (provider=0x7fffdebcb9e0, format=0x7fffdebcdef8, arg0=0x7fffdebcdf18) at obj/Debug/dnxcore50/native/Hello.cpp:9349
#9 0x00000000004406e6 in System_IO::System::IO::TextWriter::WriteLine_14 (_this=0x7fffdebcde60, format=0x7fffdebcdef8, arg0=0x7fffdebcdf18) at obj/Debug/dnxcore50/native/Hello.cpp:21775
#10 0x0000000000441163 in System_Console::System::Console::WriteLine_14 (format=0x7fffdebcdef8, arg0=0x7fffdebcdf18) at obj/Debug/dnxcore50/native/Hello.cpp:21912
#11 0x000000000048f599 in Hello::Program::Main (args=0x7fffdebcb060) at /home/tarek/oss/corert/tests/src/Simple/Hello/Hello.cs:11
#12 0x000000000048f2da in Hello::Module::StartupCodeMain (_a0=0, _a1=140737488346992) at obj/Debug/dnxcore50/native/Hello.cpp:45120
#13 0x00000000004aa93c in main (argc=1, argv=0x7fffffffdf68) at /home/tarek/oss/corert/tests/src/Simple/Hello/Hello.cs:7311

[jkotas]

Same problem as #742. The following line requires reflection:

provider.GetFormat(typeof(ICustomFormatter));

[jkotas]

Closing as dup