F# compiler should set major version of Embedded PDB

[eerhardt]

When using DebugType=embedded with F# projects, and then trying to load the resulting library with PEReader, I am getting an exception. This is because PEReader is validating that the version is at least the expected version:

https://github.com/dotnet/corefx/blob/a10890f4ffe0fadf090c922578ba0e606ebdd16c/src/System.Reflection.Metadata/src/System/Reflection/PortableExecutable/PEReader.EmbeddedPortablePdb.cs#L52-L70

Repro steps

Provide the steps required to reproduce the problem:

1. Set <DebugType>embedded</DebugType> in a .NET Standard .fsproj
2. Build
3. Pass the built .dll into the following code:

string filename = ...;
using (var fileStream = File.OpenRead(filename))
{
    PEReader reader = new PEReader(fileStream);

    foreach (var entry in reader.ReadDebugDirectory())
    {
        if (entry.Type == DebugDirectoryEntryType.EmbeddedPortablePdb)
        {
            reader.ReadEmbeddedPortablePdbDebugDirectoryData(entry);
        }
    }
}

Expected behavior

PEReader shouldn't throw on the assembly.

Actual behavior

System.BadImageFormatException
  HResult=0x8007000B
  Message=Unsupported format version: 0.0
  Source=System.Reflection.Metadata
  StackTrace:
   at System.Reflection.PortableExecutable.PEReader.ValidateEmbeddedPortablePdbVersion(DebugDirectoryEntry entry) in F:\workspace\_work\1\s\src\System.Reflection.Metadata\src\System\Reflection\PortableExecutable\PEReader.EmbeddedPortablePdb.cs:line 62

Known workarounds

Don't use embedded PDBs.

cc @KevinRansom @tmat

[KevinRansom]

@eerhardt,
This is a bug in the validation code.

the portable pdb specification says this about version:
https://github.com/dotnet/corefx/blob/master/src/System.Reflection.Metadata/specs/PE-COFF.md#embedded-portable-pdb-debug-directory-entry-type-17

Version Major=### any, Minor=0x0100 of the data format:

Declares that debugging information is embedded in the PE file at location specified by PointerToRawData.
Version Major=any, Minor=0x0100 of the data format:

@brettfo, @tmat