Fix a swift-testing build issue

This follows swiftlang/swift@ff0f923

Author: hjyamauchi

.github/workflows/swift-toolchain.yml

@@ -2189,6 +2189,8 @@ jobs:
                 -D SWIFT_ANDROID_NDK_PATH=${NDKPATH} `
                 -G Ninja `
                 -S ${{ github.workspace }}/SourceCache/swift-testing `
+                -D dispatch_DIR=${{ github.workspace }}/BinaryCache/libdispatch/cmake/modules `
+                -D Foundation_DIR=${{ github.workspace }}/BinaryCache/foundation/cmake/modules `
                 -D SwiftTesting_MACRO=${{ github.workspace }}/BinaryCache/Library/Developer/Toolchains/unknown-Asserts-development.xctoolchain/usr/bin/TestingMacros.dll
       - name: Build Testing
         run: |