[ms] [llvm-ml] Add support for .radix directive, and accept all radix specifiers

[ms] [llvm-ml] Add support for .radix directive, and accept all radix specifiers

Add support for .radix directive, and radix specifiers [yY] (binary), [oOqQ] (octal), and [tT] (decimal).

Also, when lexing MASM integers, require radix specifier; MASM requires that all literals without a radix specifier be treated as in the default radix. (e.g., 0100 = 100)

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D87400