Update java.yml

Author: Thespica

.github/workflows/java.yml

@@ -82,4 +82,5 @@ jobs:
           # Temporarily using Java 8, related issue: https://github.com/apache/incubator-graphar/issues/277
           export JAVA_HOME=${JAVA_HOME_8_X64}
           export LLVM11_HOME=/usr/lib/llvm-11
+          export GAR_TEST_DATA=$PWD/../../testing/
           mvn --no-transfer-progress clean test -Dspotless.check.skip=true