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

android/bazel_handler_test.go

@@ -101,7 +101,7 @@ func TestInvokeBazelPopulatesBuildStatements(t *testing.T) {
 func testBazelContext(t *testing.T, bazelCommandResults map[bazelCommand]string) (*bazelContext, string) {
 	t.Helper()
 	p := bazelPaths{
-		buildDir:     t.TempDir(),
+		soongOutDir:  t.TempDir(),
 		outputBase:   "outputbase",
 		workspaceDir: "workspace_dir",
 	}
@@ -114,5 +114,5 @@ func testBazelContext(t *testing.T, bazelCommandResults map[bazelCommand]string)
 		bazelRunner: runner,
 		paths:       &p,
 		requests:    map[cqueryKey]bool{},
-	}, p.buildDir
+	}, p.soongOutDir
 }