Unconditionally include the "message", if any, in SimpleSpawnResult. This is the same logic as used in Google-internal code. This allows us to stop passing the verboseFailures boolean around everywhere, since it's then only needed in one place in AbstractSpawnStrategy.

I don't think this justifies a RELNOTES, but ok if you'd prefer one.

#11151

PiperOrigin-RevId: 333156319
diff --git a/src/test/java/com/google/devtools/build/lib/actions/SpawnResultTest.java b/src/test/java/com/google/devtools/build/lib/actions/SpawnResultTest.java
index 2e9b0ff..108bf66 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/SpawnResultTest.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/SpawnResultTest.java
@@ -41,7 +41,7 @@
             .setExitCode(SpawnResult.POSIX_TIMEOUT_EXIT_CODE)
             .setRunnerName("test")
             .build();
-    assertThat(r.getDetailMessage("", "", false, false, false))
+    assertThat(r.getDetailMessage("", "", false, false))
         .contains("(failed due to timeout after 5.00 seconds.)");
   }
 
@@ -53,8 +53,7 @@
             .setExitCode(SpawnResult.POSIX_TIMEOUT_EXIT_CODE)
             .setRunnerName("test")
             .build();
-    assertThat(r.getDetailMessage("", "", false, false, false))
-        .contains("(failed due to timeout.)");
+    assertThat(r.getDetailMessage("", "", false, false)).contains("(failed due to timeout.)");
   }
 
   @Test