Upgrade to Aspectj 1.9.4

Closes gh-16844

Author: snicoll

spring-boot-project/spring-boot-dependencies/pom.xml

@@ -38,7 +38,7 @@
 		<antlr2.version>2.7.7</antlr2.version>
 		<appengine-sdk.version>1.9.74</appengine-sdk.version>
 		<artemis.version>2.8.0</artemis.version>
-		<aspectj.version>1.9.3</aspectj.version>
+		<aspectj.version>1.9.4</aspectj.version>
 		<assertj.version>3.12.2</assertj.version>
 		<atomikos.version>4.0.6</atomikos.version>
 		<bitronix.version>2.1.4</bitronix.version>