Use fixed name for SpringApplication command line args property source

Closes gh-8680

spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -490,7 +490,7 @@ public class SpringApplication {
 				PropertySource<?> source = sources.get(name);
 				CompositePropertySource composite = new CompositePropertySource(name);
 				composite.addPropertySource(new SimpleCommandLinePropertySource(
-						name + "-" + args.hashCode(), args));
+						"springApplicationCommandLineArgs", args));
 				composite.addPropertySource(source);
 				sources.replace(name, composite);
 			}

spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -497,6 +497,15 @@ public class SpringApplicationTests {
 		assertThat(environment.getProperty("bar")).isEqualTo("foo");
 		// New command line properties take precedence
 		assertThat(environment.getProperty("foo")).isEqualTo("bar");
+		CompositePropertySource composite = (CompositePropertySource) environment
+				.getPropertySources().get("commandLineArgs");
+		assertThat(composite.getPropertySources()).hasSize(2);
+		assertThat(composite.getPropertySources()).first().matches(
+				(source) -> source.getName().equals("springApplicationCommandLineArgs"),
+				"is named springApplicationCommandLineArgs");
+		assertThat(composite.getPropertySources()).element(1).matches(
+				(source) -> source.getName().equals("commandLineArgs"),
+				"is named commandLineArgs");
 	}
 
 	@Test