Rename no_standard_libraries to no_standard_libs

For consistency with libs and static_libs.  And make it a *bool
so that it can be overriden when used in java_defaults modules.

Test: java_test.go
Change-Id: If0eaf5d5571dc6e565056d273b0addd960d6b33f

java/java_test.go

@@ -69,7 +69,7 @@ func testJava(t *testing.T, bp string) *android.TestContext {
 		bp += fmt.Sprintf(`
 			java_library {
 				name: "%s",
-				no_standard_libraries: true,
+				no_standard_libs: true,
 			}
 		`, extra)
 	}