Output informational messages only when BP2BUILD_VERBOSE is set.

Test: manual
Change-Id: Ieeb00a002e07b04449d70614ce205c47c1dd7bce

cmd/soong_build/main.go

@@ -552,7 +552,7 @@ func runBp2Build(configuration android.Config, extraNinjaDeps []string) {
 		excludes = append(excludes, getTemporaryExcludes()...)
 
 		symlinkForestDeps := bp2build.PlantSymlinkForest(
-			topDir, workspaceRoot, generatedRoot, ".", excludes)
+			configuration, topDir, workspaceRoot, generatedRoot, ".", excludes)
 
 		ninjaDeps = append(ninjaDeps, codegenContext.AdditionalNinjaDeps()...)
 		ninjaDeps = append(ninjaDeps, symlinkForestDeps...)
@@ -566,7 +566,9 @@ func runBp2Build(configuration android.Config, extraNinjaDeps []string) {
 	// Only report metrics when in bp2build mode. The metrics aren't relevant
 	// for queryview, since that's a total repo-wide conversion and there's a
 	// 1:1 mapping for each module.
-	metrics.Print()
+	if configuration.IsEnvTrue("BP2BUILD_VERBOSE") {
+		metrics.Print()
+	}
 	writeBp2BuildMetrics(&metrics, configuration, eventHandler)
 }