Adjust incrementalCompilationCachingBasic to reproduce issue 88113

Need to not use load module interface to reproduce issue 88113

Author: hjyamauchi

Tests/SwiftDriverTests/Helpers/IncrementalTestHarness.swift

@@ -157,7 +157,7 @@ final class IncrementalTestHarness {
     }
   }
 
-  init(config: TestBuildConfig = .implicitModule) throws {
+  init(config: TestBuildConfig = .implicitModule, preferInterfaceModuleLoadMode: Bool = true) throws {
     self.config = config
 
     guard let sdkArgs = try Driver.sdkArgumentsForTesting() else {
@@ -204,7 +204,7 @@ final class IncrementalTestHarness {
 
     Thread.sleep(forTimeInterval: 1)
     let driver = try! Driver(args: ["swiftc"])
-    if driver.isFrontendArgSupported(.moduleLoadMode) {
+    if preferInterfaceModuleLoadMode && driver.isFrontendArgSupported(.moduleLoadMode) {
       self.extraExplicitBuildArgs = ["-Xfrontend", "-module-load-mode", "-Xfrontend", "prefer-interface"]
     }
   }

Tests/SwiftDriverTests/IncrementalExplicitBuildTests.swift

@@ -44,7 +44,8 @@ struct IncrementalExplicitBuildTests: DiagVerifiable {
 
   @Test(.serialized, arguments: TestBuildConfig.cachingConfigs)
   func incrementalCompilationCachingBasic(config: TestBuildConfig) async throws {
-    let h = try IncrementalTestHarness(config: config)
+    // Set preferInterfaceModuleLoadMode false to reproduce the issue 88113
+    let h = try IncrementalTestHarness(config: config, preferInterfaceModuleLoadMode: false)
     try h.buildInitialState(checkDiagnostics: false)
     try h.touch("other")
     try h.doABuild(