Only pass -handshaker-path in split handshakes tests.

This is a little inconvenient for external users of the test suite. It's
also not very helpful to pass -handshaker-path in build configurations
without a handshaker because there won't be a file there anyway.

Change-Id: I6a8fdcfbbf86288876c4c6fda2a46d32663efb69
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/46244
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index dd3c08c..d5da2ab 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -1463,8 +1463,6 @@
 		flags = append(flags, "-tls-unique")
 	}
 
-	flags = append(flags, "-handshaker-path", *handshakerPath)
-
 	if *waitForDebugger {
 		flags = append(flags, "-wait-for-debugger")
 	}
@@ -1857,7 +1855,7 @@
 		shTest.name += "-Split"
 		shTest.flags = make([]string, len(test.flags), len(test.flags)+1)
 		copy(shTest.flags, test.flags)
-		shTest.flags = append(shTest.flags, "-handoff")
+		shTest.flags = append(shTest.flags, "-handoff", "-handshaker-path", *handshakerPath)
 
 		splitHandshakeTests = append(splitHandshakeTests, shTest)
 	}