Update testExecutableFallbackPath to pass on all platforms

Amazon Linux 2023 includes a dsymutil in its LLVM package, which is
installed on our builders (checking separately if that is actually
required). The intent of this test seems to be mostly to make sure we
are able to find all tools when allowing fallbacks, so update it to just
check for that.

Author: bnbarham

Tests/SwiftDriverTests/SwiftDriverTests.swift

@@ -5693,15 +5693,10 @@ final class SwiftDriverTests: XCTestCase {
   }
 
   func testExecutableFallbackPath() throws {
-    let driver1 = try Driver(args: ["swift", "main.swift"])
-    if !driver1.targetTriple.isDarwin {
-      XCTAssertThrowsError(try driver1.toolchain.getToolPath(.dsymutil))
-    }
-
     var env = ProcessEnv.block
     env["SWIFT_DRIVER_TESTS_ENABLE_EXEC_PATH_FALLBACK"] = "1"
-    let driver2 = try Driver(args: ["swift", "main.swift"], env: env)
-    XCTAssertNoThrow(try driver2.toolchain.getToolPath(.dsymutil))
+    let driver = try Driver(args: ["swift", "main.swift"], env: env)
+    XCTAssertNoThrow(try driver.toolchain.getToolPath(.dsymutil))
   }
 
   func testVersionRequest() throws {