[ExplicitModule] Include -Xcc -D into module hash

The decision to exclude `-Xcc -D` options from swift module hash
actually doesn't help to solve the problem. It wouldn't reduce the
module variants (or the number of swiftmodule build commands) because
the command-line also encodes all the clang PCM dependencies that do get
affected by `-Xcc` flags.

To avoid the false sharing and the nondeterministic build products,
include most of the `-Xcc` flags, except include search path, into swift
module hash.

rdar://132046247

lib/DependencyScan/ModuleDependencyScanner.cpp

@@ -383,8 +383,7 @@ ModuleDependencyScanner::getMainModuleDependencyInfo(ModuleDecl *mainModule) {
   std::vector<std::string> buildArgs;
   if (ScanASTContext.ClangImporterOpts.ClangImporterDirectCC1Scan) {
     buildArgs.push_back("-direct-clang-cc1-module-build");
-    for (auto &arg : clangImporter->getSwiftExplicitModuleDirectCC1Args(
-             /*isInterface=*/false)) {
+    for (auto &arg : clangImporter->getSwiftExplicitModuleDirectCC1Args()) {
       buildArgs.push_back("-Xcc");
       buildArgs.push_back(arg);
     }