Summary:
There was an issue on `make build_ant_test` that newly generated `issues.exp.test` is empty. When
infer runs with `-- ant`, if there is already built objects in `ant_out`, infer analyzes nothing,
which result in the empty `issues.exp.test`. For example,
```
~/infer/infer/tests/build_systems/ant$ make test
[11:26:49][36924] Testing ant integration...
[ 2s][36924] SUCCESS Testing ant integration
~/infer/infer/tests/build_systems/ant$ touch `which infer`
```
The makefile tries to reanalyze ant targets because `infer` binary has been changed. However, there
is nothing to build/analyze, since `ant_out` still exists as the same.
```
~/infer/infer/tests/build_systems/ant$ make test
[11:26:57][37078] Testing ant integration...
[ 1s][37078] SUCCESS Testing ant integration
diff --git a/Users/scho/infer/infer/tests/build_systems/ant/issues.exp b/Users/scho/infer/infer/tests/build_systems/ant/issues.exp.test
index 376146b5f..e69de29bb 100644
--- a/Users/scho/infer/infer/tests/build_systems/ant/issues.exp
+++ b/Users/scho/infer/infer/tests/build_systems/ant/issues.exp.test
@@ -1 +0,0 @@
[-build_systems/ant/src/Hello.java, Hello.test():int, 2, NULL_DEREFERENCE, no_bucket, ERROR, [start of procedure test()]-]
Test output (build_systems/ant/issues.exp.test) differs from expected test output build_systems/ant/issues.exp
Run the following command to replace the expected test output with the new output:
make -C build_systems/ant replace
make: *** [test] Error 1
```
To handle this issue, this cleans `ant_out` before running infer.
Reviewed By: jvillard
Differential Revision: D21950916
fbshipit-source-id: f57056f6e
Sungkeun Cho
e611f0e8b3