[Dependency Scanning] Use clang dependency scanning tool's old by-name lookup API (#86733)

https://github.com/swiftlang/swift/pull/85555 taught Swift to use a
shared clang compiler instance that is initialized once and reused for
multiple by-name lookups. This unfortunately led to a few internal
project build failures.

This PR reverts back to use clang dependency scanning tool's old by-name
lookup APIs while we investigate the failures.

rdar://168709914

lib/DependencyScan/ModuleDependencyScanner.cpp

@@ -326,9 +326,10 @@ ModuleDependencyScanningWorker::scanFilesystemForClangModuleDependency(
     const llvm::DenseSet<clang::tooling::dependencies::ModuleID>
         &alreadySeenModules) {
   diagnosticReporter.registerNamedClangModuleQuery();
-  auto clangModuleDependencies =
-      clangScanningTool.computeDependenciesByNameWithContext(
-          moduleName.str(), alreadySeenModules, lookupModuleOutput);
+  auto clangModuleDependencies = clangScanningTool.getModuleDependencies(
+      moduleName.str(), clangScanningModuleCommandLineArgs,
+      clangScanningWorkingDirectoryPath, alreadySeenModules,
+      lookupModuleOutput);
   if (!clangModuleDependencies) {
     llvm::handleAllErrors(
         clangModuleDependencies.takeError(),