Various cleanup in soong_ui to aid new feature

- Rename the "BuildX" variables to "RunX"
- Remove redundant comments
- Inline all the "what to do" based on config in build.go
- Inline some constants only used in one place

Bug: 189187214
Test: m nothing
Test: build/soong/build_test.bash
Change-Id: I111a69e642212d7938d4971283545e0d9acbb01a
Merged-In: I111a69e642212d7938d4971283545e0d9acbb01a
(cherry picked from commit d274ea91968b95ef7a2edd2d604afbc237e84ff9)
diff --git a/cmd/multiproduct_kati/main.go b/cmd/multiproduct_kati/main.go
index 20f146a..55a5470 100644
--- a/cmd/multiproduct_kati/main.go
+++ b/cmd/multiproduct_kati/main.go
@@ -460,19 +460,21 @@
 		}
 	}()
 
-	buildWhat := build.BuildProductConfig
+	config.SetSkipNinja(true)
+
+	buildWhat := build.RunProductConfig
 	if !*onlyConfig {
-		buildWhat |= build.BuildSoong
+		buildWhat |= build.RunSoong
 		if !*onlySoong {
-			buildWhat |= build.BuildKati
+			buildWhat |= build.RunKati
 		}
 	}
 
 	before := time.Now()
-	build.Build(ctx, config, buildWhat)
+	build.Build(ctx, config)
 
 	// Save std_full.log if Kati re-read the makefiles
-	if buildWhat&build.BuildKati != 0 {
+	if buildWhat&build.RunKati != 0 {
 		if after, err := os.Stat(config.KatiBuildNinjaFile()); err == nil && after.ModTime().After(before) {
 			err := copyFile(stdLog, filepath.Join(filepath.Dir(stdLog), "std_full.log"))
 			if err != nil {
diff --git a/cmd/soong_ui/main.go b/cmd/soong_ui/main.go
index 390a9ec..22922c0 100644
--- a/cmd/soong_ui/main.go
+++ b/cmd/soong_ui/main.go
@@ -59,12 +59,10 @@
 	run func(ctx build.Context, config build.Config, args []string, logsDir string)
 }
 
-const makeModeFlagName = "--make-mode"
-
 // list of supported commands (flags) supported by soong ui
 var commands []command = []command{
 	{
-		flag:        makeModeFlagName,
+		flag:        "--make-mode",
 		description: "build the modules by the target name (i.e. soong_docs)",
 		config: func(ctx build.Context, args ...string) build.Config {
 			return build.NewConfig(ctx, args...)
@@ -506,15 +504,7 @@
 		ctx.Fatal("done")
 	}
 
-	toBuild := build.BuildAll
-	if config.UseBazel() {
-		toBuild = build.BuildAllWithBazel
-	}
-
-	if config.Checkbuild() {
-		toBuild |= build.RunBuildTests
-	}
-	build.Build(ctx, config, toBuild)
+	build.Build(ctx, config)
 }
 
 // getCommand finds the appropriate command based on args[1] flag. args[0]