Rename BuildDir and NinjaBuildDir.

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

Test: Presubmits.
Merged-In: I999ca62162062f27e449f83ffb00fa580d4065b8
Merged-In: I2fcd80a9e376a6842a06aa104a9f6f5c5e16f8c7
Change-Id: Ib481d2aac40df8da1b74174dc8ec576c1cb48be0
diff --git a/apex/apex_test.go b/apex/apex_test.go
index b9285ae..e0bf5e5 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -4930,7 +4930,7 @@
 			}
 		}
 		if !foundLibfooJar {
-			t.Errorf("Rule for libfoo.jar missing in dex_bootjars singleton outputs %q", android.StringPathsRelativeToTop(ctx.Config().BuildDir(), s.AllOutputs()))
+			t.Errorf("Rule for libfoo.jar missing in dex_bootjars singleton outputs %q", android.StringPathsRelativeToTop(ctx.Config().SoongOutDir(), s.AllOutputs()))
 		}
 	}