Simplify Travis-CI build configuration for PR

Remove the before_install sections completely
Remove the customized build matrix and use built-in matrix generation

Signed-off-by: Emily Mabrey <[email protected]>

Author: emabrey

.travis.yml

@@ -4,17 +4,11 @@ sudo: false
 # http://docs.travis-ci.com/user/languages/java/
 language: java
 
-matrix:
-    include:
-      - jdk: openjdk8
-      - jdk: openjdk9
-      - jdk: openjdk10
-      - jdk: openjdk11
-      - jdk: oraclejdk8
-      - jdk: oraclejdk10
-    allow_failures:
-      - jdk: openjdk-ea
-      - jdk: oraclejdk-ea
+jdk:
+  - openjdk8
+  - oraclejdk8
+  - oraclejdk9
+  - oraclejdk11
 
 #Cache downloaded Maven artifacts between builds
 cache: