swiftpm: Test only running host platform architecture

When adding a Swift Testing test to Swift PM repository, the `test`
portion of t he OSX package pipeline was building against x86_64 and
arm64.

Ensure Swift PM testing only runs against the host platform
architecture.

 .

Author: bkhouri

utils/build-presets.ini

@@ -1846,6 +1846,7 @@ swift-testing-macros
 install-swift-testing
 install-swift-testing-macros
 
+infer-cross-compile-hosts-on-darwin
 skip-test-swift
 
 [preset: mixin_swiftpm_macos_platform]

utils/swift_build_support/swift_build_support/products/swiftpm.py

@@ -42,7 +42,14 @@ def is_before_build_script_impl_product(cls):
     def should_build(self, host_target):
         return True
 
-    def run_bootstrap_script(self, action, host_target, additional_params=[]):
+    def run_bootstrap_script(
+            self,
+            action,
+            host_target,
+            additional_params=[],
+            *,
+            compile_only_for_running_host_architecture = False,
+    ):
         script_path = os.path.join(
             self.source_dir, 'Utilities', 'bootstrap')
 
@@ -85,7 +92,7 @@ def run_bootstrap_script(self, action, host_target, additional_params=[]):
             ]
 
         # Pass Cross compile host info
-        if self.has_cross_compile_hosts():
+        if not compile_only_for_running_host_architecture and self.has_cross_compile_hosts():
             if self.is_darwin_host(host_target):
                 helper_cmd += ['--cross-compile-hosts']
                 for cross_compile_host in self.args.cross_compile_hosts:
@@ -114,7 +121,11 @@ def should_test(self, host_target):
         return self.args.test_swiftpm
 
     def test(self, host_target):
-        self.run_bootstrap_script('test', host_target)
+        self.run_bootstrap_script(
+            'test',
+            host_target,
+            compile_only_for_running_host_architecture=True,
+        )
 
     def should_clean(self, host_target):
         return self.args.clean_swiftpm