Re-enable the bannedThrow check

It's been disabled previously due to pre-existing failures. Baseline
those and remove the disabling.

Bug: 222738070
Test: m checkapi
Ignore-AOSP-First: This error is not being re-enabled in AOSP yet
Change-Id: Ia4f91f1470a5bce332df1896b81550276c4b174d

java/config/droidstubs.go

@@ -50,8 +50,6 @@ var (
 		"--hide HiddenTypedefConstant",
 		"--hide SuperfluousPrefix",
 		"--hide AnnotationExtraction",
-		// b/222738070
-		"--hide BannedThrow",
 	}
 
 	MetalavaAnnotationsWarningsFlags = strings.Join(metalavaAnnotationsWarningsFlags, " ")