[clang][cli] NFC: Add PIE parsing for precompiled input and IR

[jansvoboda11]

Summary

This patch effectively reverts a small part of D83979.

When we stop parsing LangOpts unconditionally in parseSimpleArgs (above the diff) and move them back to ParseLangArgs (called in else branch) in D94682, LangOpts.PIE would never get parsed in this if branch. This patch ensures this doesn't happen.

Right now, this causes LangOpts.PIE to be parsed twice, but that will be immediately corrected in D94682.

[Bigcheese]

LGTM.

clang/lib/Frontend/CompilerInvocation.cpp

 //===- CompilerInvocation.cpp ---------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
if (DashX.getFormat() == InputKind::Precompiled ||
     // ObjCAAutoRefCount and Sanitize LangOpts are used to setup the
     // PassManager in BackendUtil.cpp. They need to be initializd no matter
     // what the input type is.
     if (Args.hasArg(OPT_fobjc_arc))
       LangOpts.ObjCAutoRefCount = 1;
     // PIClevel and PIELevel are needed during code generation and this should be
     // set regardless of the input type.
     LangOpts.PICLevel = getLastArgIntValue(Args, OPT_pic_level, 0, Diags);
+    LangOpts.PIE = Args.hasArg(OPT_pic_is_pie);
     parseSanitizerKinds("-fsanitize=", Args.getAllArgValues(OPT_fsanitize_EQ),
                         Diags, LangOpts.Sanitize);
   } else {
     // Other LangOpts are only initialized when the input is not AST or LLVM IR.
     // FIXME: Should we really be calling this for an Language::Asm input?
     ParseLangArgs(LangOpts, Args, DashX, T, Res.getPreprocessorOpts().Includes,
                   Diags);
     if (Res.getFrontendOpts().ProgramAction == frontend::RewriteObjC)