Add command line flag for extra bazel-built modules

Test: m libcore --bazel-mode-staging --bazel-force-enabled-modules=libcore and find out/bazel/ -name libcore*

Change-Id: I065696d06ce07e05300a41e133867a6e7a891b5e
diff --git a/android/bazel_handler.go b/android/bazel_handler.go
index cf74b9c..122495f 100644
--- a/android/bazel_handler.go
+++ b/android/bazel_handler.go
@@ -387,6 +387,10 @@
 		for _, enabledProdModule := range allowlists.ProdMixedBuildsEnabledList {
 			enabledModules[enabledProdModule] = true
 		}
+
+		for enabledAdHocModule := range c.BazelModulesForceEnabledByFlag() {
+			enabledModules[enabledAdHocModule] = true
+		}
 	case BazelStagingMode:
 		modulesDefaultToBazel = false
 		// Staging mode includes all prod modules plus all staging modules.
@@ -396,6 +400,10 @@
 		for _, enabledStagingMode := range allowlists.StagingMixedBuildsEnabledList {
 			enabledModules[enabledStagingMode] = true
 		}
+
+		for enabledAdHocModule := range c.BazelModulesForceEnabledByFlag() {
+			enabledModules[enabledAdHocModule] = true
+		}
 	case BazelDevMode:
 		modulesDefaultToBazel = true