Rename BuildDir and NinjaBuildDir.

These are just out/ and out/soong/ and the old names were quite
confusing.

Test: Presubmits.
Change-Id: I999ca62162062f27e449f83ffb00fa580d4065b8

java/app_test.go

@@ -1737,7 +1737,7 @@ func TestPackageNameOverride(t *testing.T) {
 
 			foo := result.ModuleForTests("foo", "android_common")
 
-			outSoongDir := result.Config.BuildDir()
+			outSoongDir := result.Config.SoongOutDir()
 
 			outputs := foo.AllOutputs()
 			outputMap := make(map[string]bool)

java/base.go

@@ -793,7 +793,7 @@ func (j *Module) collectJavacFlags(
 			// Manually specify build directory in case it is not under the repo root.
 			// (javac doesn't seem to expand into symbolic links when searching for patch-module targets, so
 			// just adding a symlink under the root doesn't help.)
-			patchPaths := []string{".", ctx.Config().BuildDir()}
+			patchPaths := []string{".", ctx.Config().SoongOutDir()}
 
 			// b/150878007
 			//

java/java_test.go

@@ -1183,7 +1183,7 @@ func checkPatchModuleFlag(t *testing.T, ctx *android.TestContext, moduleName str
 			break
 		}
 	}
-	if expected != android.StringPathRelativeToTop(ctx.Config().BuildDir(), got) {
+	if expected != android.StringPathRelativeToTop(ctx.Config().SoongOutDir(), got) {
 		t.Errorf("Unexpected patch-module flag for module %q - expected %q, but got %q", moduleName, expected, got)
 	}
 }