Remove some unused args from Blueprint.

These are: TopFile and GeneratingPrimaryBuilder.

Also re-shuffle the list of flags to make a bit more sense and finish
the rename of BuildDir and NinjaBuildDir to SoongOutDir and OutDir,
respectively.

Test: Presubmits.
Change-Id: I103ff5f09f1c0d16f695a7da5dea13b55028e33e
diff --git a/android/paths.go b/android/paths.go
index a733558..763cd7c 100644
--- a/android/paths.go
+++ b/android/paths.go
@@ -1150,7 +1150,7 @@
 type OutputPath struct {
 	basePath
 
-	// The soong build directory, i.e. Config.BuildDir()
+	// The soong build directory, i.e. Config.SoongOutDir()
 	soongOutDir string
 
 	fullPath string
@@ -1544,7 +1544,7 @@
 type InstallPath struct {
 	basePath
 
-	// The soong build directory, i.e. Config.BuildDir()
+	// The soong build directory, i.e. Config.SoongOutDir()
 	soongOutDir string
 
 	// partitionDir is the part of the InstallPath that is automatically determined according to the context.