[cxx-interop] Do not pass -tools-directory in tests

ClangImporter is now able to find the C++ stdlib on its own, let's not provide any explicit options that control this in tests.

rdar://119869070

Author: egorzhdan

test/Interop/Cxx/stdlib/libcxx-module-interface.swift

@@ -1,7 +1,7 @@
-// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib -source-filename=x -enable-experimental-cxx-interop -tools-directory=%llvm_obj_root/bin -module-cache-path %t | %FileCheck %s  -check-prefix=CHECK-STD
-// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib -source-filename=x -enable-experimental-cxx-interop -tools-directory=%llvm_obj_root/bin -module-cache-path %t -module-print-submodules | %FileCheck %s  -check-prefix=CHECK-STD-WITH-SUBMODULES
-// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib.iosfwd -source-filename=x -enable-experimental-cxx-interop -tools-directory=%llvm_obj_root/bin -module-cache-path %t | %FileCheck %s  -check-prefix=CHECK-IOSFWD
-// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib.string -source-filename=x -enable-experimental-cxx-interop -tools-directory=%llvm_obj_root/bin -module-cache-path %t | %FileCheck %s  -check-prefix=CHECK-STRING
+// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib -source-filename=x -enable-experimental-cxx-interop -module-cache-path %t | %FileCheck %s  -check-prefix=CHECK-STD
+// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib -source-filename=x -enable-experimental-cxx-interop -module-cache-path %t -module-print-submodules | %FileCheck %s  -check-prefix=CHECK-STD-WITH-SUBMODULES
+// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib.iosfwd -source-filename=x -enable-experimental-cxx-interop -module-cache-path %t | %FileCheck %s  -check-prefix=CHECK-IOSFWD
+// RUN: %target-swift-ide-test -print-module -module-to-print=CxxStdlib.string -source-filename=x -enable-experimental-cxx-interop -module-cache-path %t | %FileCheck %s  -check-prefix=CHECK-STRING
 
 // This test is specific to libc++ and therefore only runs on Darwin platforms.
 // REQUIRES: OS=macosx || OS=ios

test/Interop/Cxx/stdlib/use-cxxstdlib-types-in-module-interface.swift

@@ -1,7 +1,7 @@
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
-// RUN: %target-swift-ide-test -swift-version 5 -print-module -module-to-print=IncludesCxxStdlib -I %t/Inputs -source-filename=test.swift -enable-experimental-cxx-interop -tools-directory=%llvm_obj_root/bin -module-cache-path %t/cache | %FileCheck %s
+// RUN: %target-swift-ide-test -swift-version 5 -print-module -module-to-print=IncludesCxxStdlib -I %t/Inputs -source-filename=test.swift -enable-experimental-cxx-interop -module-cache-path %t/cache | %FileCheck %s
 
 //--- Inputs/module.modulemap
 module IncludesCxxStdlib {