[SystemZ][z/OS] Add IsText Argument to GetFile and GetFileOrSTDIN

Add the `IsText` argument to `GetFile` and `GetFileOrSTDIN` which will help z/OS distinguish between text and binary correctly. This is an extension to [this patch](https://reviews.llvm.org/D97785)

Reviewed By: abhina.sreeskantharajan, amccarth

Differential Revision: https://reviews.llvm.org/D100488

GitOrigin-RevId: e71994a239d5f807c1c75515bfa512495224469f
diff --git a/tools/driver/cc1as_main.cpp b/tools/driver/cc1as_main.cpp
index 570e3e4..083fc08 100644
--- a/tools/driver/cc1as_main.cpp
+++ b/tools/driver/cc1as_main.cpp
@@ -342,7 +342,7 @@
     return Diags.Report(diag::err_target_unknown_triple) << Opts.Triple;
 
   ErrorOr<std::unique_ptr<MemoryBuffer>> Buffer =
-      MemoryBuffer::getFileOrSTDIN(Opts.InputFile);
+      MemoryBuffer::getFileOrSTDIN(Opts.InputFile, /*IsText=*/true);
 
   if (std::error_code EC = Buffer.getError()) {
     Error = EC.message();