Parsing multi-line messages from XCTFail can produce inaccurate results

[adam-fowler]

It is very hard to identify when an XCTFail message finishes in the output from XCTest.

The following test

func testXCTFail() {
    XCTFail("""
    Test
    Failed
    """)
    print("Hello")
}

produces the following output

Test Case 'AppTests.testXCTFail' started at 2023-01-14 12:38:26.859
/workspaces/Tests/AppTests/AppTests.swift:21: error: AppTests.testFail : failed - Test
Failed
Hello
Test Case 'AppTests.testFail' failed (0.006 seconds)

There is no way from this output to ascertain where the fail message ends.

This is an issue for the VSCode Swift extension when parsing XCTest output to update the TestExplorer

swift --version output

Swift version 5.8-dev (LLVM 170e2cfa496ad7c, Swift f32ae6f8c6068cd)
Target: aarch64-unknown-linux-gnu

This is an issue on all platforms

[grynspan]

Duplicate of #361