Improve the binary compatibility of runTest$default further (#3753)

Follow-up to #3742.
That implementation there did work around issue #3673, but did not restore full binary compatibility: the wrong value of `dispatchTimeoutMs` was passed. Given how `runTest` was used in the problematic library, it should not be a problem, but just to be safe and establish the same behavior even in the deep corner cases, we restore the original implementation fully.

Author: dkhalanskyjb

kotlinx-coroutines-test/common/src/TestBuilders.kt

@@ -580,6 +580,6 @@ internal expect fun dumpCoroutines()
 public fun TestScope.runTestLegacy(
     dispatchTimeoutMs: Long,
     testBody: suspend TestScope.() -> Unit,
-    unused1: Int,
+    marker: Int,
     unused2: Any?,
-): TestResult = runTest(dispatchTimeoutMs, testBody)
+): TestResult = runTest(dispatchTimeoutMs = if (marker and 1 != 0) dispatchTimeoutMs else 60_000L, testBody)