Automatically call TestingBuildParams.RelativeToTop()

Fixes the few tests that break due to this and which cannot easily be
separated into their own changes.

Bug: 183650682
Test: m nothing
Change-Id: Ia2f31213a1f114a78e66a81d89279ecde9f4c465
diff --git a/android/testing.go b/android/testing.go
index acec6fc..f4f5c98 100644
--- a/android/testing.go
+++ b/android/testing.go
@@ -558,7 +558,7 @@
 		return p
 	}
 	if p.config.config == nil {
-		panic("cannot call RelativeToTop() on a TestingBuildParams previously returned by RelativeToTop()")
+		return p
 	}
 	// Take a copy of the build params and replace any args that contains test specific temporary
 	// paths with paths relative to the top.
@@ -670,7 +670,7 @@
 		config:      b.config,
 		BuildParams: bparams,
 		RuleParams:  b.provider.RuleParamsForTests()[bparams.Rule],
-	}
+	}.RelativeToTop()
 }
 
 func (b baseTestingComponent) maybeBuildParamsFromRule(rule string) (TestingBuildParams, []string) {