Use new SPI for SourceKitLSPAPITests (swiftlang#7468)

SPI was added here in swiftlang#7465, but missed adding it to this module.

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

Author: 2 people

Tests/SPMBuildCoreTests/PluginInvocationTests.swift

@@ -11,7 +11,10 @@
 //===----------------------------------------------------------------------===//
 
 import Basics
+
+@_spi(DontAdoptOutsideOfSwiftPMExposedForBenchmarksAndTestsOnly)
 @testable import PackageGraph
+
 import PackageLoading
 import PackageModel
 @testable import SPMBuildCore

Tests/SourceKitLSPAPITests/SourceKitLSPAPITests.swift

@@ -12,7 +12,10 @@
 
 import Basics
 import Build
+
+@_spi(DontAdoptOutsideOfSwiftPMExposedForBenchmarksAndTestsOnly)
 import PackageGraph
+
 import PackageModel
 import SourceKitLSPAPI
 import SPMTestSupport