Fix test targets that depend on macros and swift-testing (#7508)

After #7353 landed, I noticed that the build products for test targets
were not being emitted correctly. swift-testing and XCTest produce
separate build products (with distinct names) but this wasn't happening
as intended. It turns out that the changes to split `buildParameters`
into `productsBuildParameters` and `toolsBuildParameters` weren't fully
propagated to our testing infrastructure.

I also noticed `SWIFT_PM_SUPPORTS_SWIFT_TESTING` wasn't being set
correctly anymore (same root cause) although we've decided to ignore
that flag over in swift-testing anyway (see
swiftlang/swift-testing#376.)

This regression caused build failures in swift-testing (e.g.
[here](https://ci.swift.org/job/pr-swift-testing-macos/663/console))
with the telltale failure signature:

>
/Users/ec2-user/jenkins/workspace/pr-swift-testing-macos/branch-main/swift-testing/.build/x86_64-apple-macosx/debug/swift-testingPackageTests.xctest/Contents/MacOS/swift-testingPackageTests:
/Users/ec2-user/jenkins/workspace/pr-swift-testing-macos/branch-main/swift-testing/.build/x86_64-apple-macosx/debug/swift-testingPackageTests.xctest/Contents/MacOS/swift-testingPackageTests:
cannot execute binary file

Which indicates that it thinks the filename for the swift-testing build
product is the XCTest bundle's executable.

This PR plumbs through the two build parameters arguments to everywhere
in `swift test` and `swift build` that needs them and resolves the
issue.

---------

Co-authored-by: Max Desiatov <[email protected]>

Author: grynspan

Sources/Commands/SwiftBuildCommand.swift

@@ -149,8 +149,7 @@ package struct SwiftBuildCommand: AsyncSwiftCommand {
             throw ExitCode.failure
         }
         if case .allIncludingTests = subset {
-            var buildParameters = try swiftCommandState.productsBuildParameters
-            for library in try options.testLibraryOptions.enabledTestingLibraries(swiftCommandState: swiftCommandState) {
+            func updateTestingParameters(of buildParameters: inout BuildParameters, library: BuildParameters.Testing.Library) {
                 buildParameters.testingParameters = .init(
                     configuration: buildParameters.configuration,
                     targetTriple: buildParameters.triple,
@@ -161,18 +160,30 @@ package struct SwiftBuildCommand: AsyncSwiftCommand {
                     testEntryPointPath: globalOptions.build.testEntryPointPath,
                     library: library
                 )
-                try build(swiftCommandState, subset: subset, buildParameters: buildParameters)
+            }
+            var productsBuildParameters = try swiftCommandState.productsBuildParameters
+            var toolsBuildParameters = try swiftCommandState.toolsBuildParameters
+            for library in try options.testLibraryOptions.enabledTestingLibraries(swiftCommandState: swiftCommandState) {
+                updateTestingParameters(of: &productsBuildParameters, library: library)
+                updateTestingParameters(of: &toolsBuildParameters, library: library)
+                try build(swiftCommandState, subset: subset, productsBuildParameters: productsBuildParameters, toolsBuildParameters: toolsBuildParameters)
             }
         } else {
-            try build(swiftCommandState, subset: subset)
+            try build(swiftCommandState, subset: subset, productsBuildParameters: nil, toolsBuildParameters: nil)
         }
     }
 
-    private func build(_ swiftCommandState: SwiftCommandState, subset: BuildSubset, buildParameters: BuildParameters? = nil) throws {
+    private func build(
+        _ swiftCommandState: SwiftCommandState,
+        subset: BuildSubset,
+        productsBuildParameters: BuildParameters?,
+        toolsBuildParameters: BuildParameters?
+    ) throws {
         let buildSystem = try swiftCommandState.createBuildSystem(
             explicitProduct: options.product,
             shouldLinkStaticSwiftStdlib: options.shouldLinkStaticSwiftStdlib,
-            productsBuildParameters: buildParameters,
+            productsBuildParameters: productsBuildParameters,
+            toolsBuildParameters: toolsBuildParameters,
             // command result output goes on stdout
             // ie "swift build" should output to stdout
             outputStream: TSCBasic.stdoutStream