Replace System.getProperties().remove(x) with System.clearProperty(x)

This commit migrates to the not-so-new System.clearProperty() method
introduced in Java 1.5.

spring-core/src/test/java/org/springframework/core/io/ResourceEditorTests.java

@@ -73,7 +73,7 @@ class ResourceEditorTests {
 			assertThat(resolved.getFilename()).isEqualTo("foo");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -87,7 +87,7 @@ class ResourceEditorTests {
 			assertThat(resolved.getFilename()).isEqualTo("foo-${bar}");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -102,7 +102,7 @@ class ResourceEditorTests {
 			});
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 

spring-core/src/test/java/org/springframework/core/io/support/ResourceArrayPropertyEditorTests.java

@@ -70,7 +70,7 @@ class ResourceArrayPropertyEditorTests {
 			assertThat(resources[0].getFilename()).isEqualTo("foo");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -85,7 +85,7 @@ class ResourceArrayPropertyEditorTests {
 					editor.setAsText("${test.prop}-${bar}"));
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 

spring-core/src/test/java/org/springframework/util/SystemPropertyUtilsTests.java

@@ -37,7 +37,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -49,7 +49,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -61,7 +61,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -73,7 +73,7 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("bar");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
+			System.clearProperty("test.prop");
 		}
 	}
 
@@ -122,8 +122,8 @@ class SystemPropertyUtilsTests {
 			assertThat(resolved).isEqualTo("foo=baz");
 		}
 		finally {
-			System.getProperties().remove("test.prop");
-			System.getProperties().remove("bar");
+			System.clearProperty("test.prop");
+			System.clearProperty("bar");
 		}
 	}