New String.TrimEnd overload breaks MSBuild CoerceArguments on netcoreapp2.0

[eerhardt]

CoreFX has added a new String.TrimEnd overload with dotnet/corefx#15334.

This is breaking MSBuild running on netcoreapp2.0 when building a project that contains logic like the following taken from dotnet/sdk:

<_ShortFrameworkIdentifier>$(TargetFramework.TrimEnd('.0123456789'))</_ShortFrameworkIdentifier>

I get the following error:

Microsoft.NET.TargetFrameworkInference.targets(51,4): error MSB4184: The expression ""netcoreapp2.0".TrimEnd(.0123456789)" cannot be evaluated. String must be exactly one character long. 

I've debugged the error down to this logic in MSBuild:

                        else
                        {
                            // change the type of the final unescaped string into the destination
                            coercedArguments[n] = Convert.ChangeType(args[n], parameters[n].ParameterType, CultureInfo.InvariantCulture);
                        }
                    }
                }
                catch (InvalidCastException)
                {
                    // The coercion failed therefore we return null
                    return null;

The issue is Convert.ChangeType is throwing a FormatException, just like it is documented to do. But this code only catches InvalidCastException. Instead, since trying to convert a string to a single char fails, this method overload should be skipped and keep searching until it finds the overload that accepts char[].

This is blocking the CLI "2.0" work from taking new builds of the .NET Core runtime.