Fix memory leak on malloc failure.

Found by running malloc tests with -valgrind. Unfortunately, the next one is
deep in crypto/asn1 itself, so I'm going to stop here for now.

Change-Id: I7a33971ee07c6b7b7a98715f2f18e0f29380c0a1
Reviewed-on: https://boringssl-review.googlesource.com/3350
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 05e20de..9b07a68 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -1053,7 +1053,8 @@
 	shim.Stdout = &stdoutBuf
 	shim.Stderr = &stderrBuf
 	if mallocNumToFail >= 0 {
-		shim.Env = []string{"MALLOC_NUMBER_TO_FAIL=" + strconv.FormatInt(mallocNumToFail, 10)}
+		shim.Env = os.Environ()
+		shim.Env = append(shim.Env, "MALLOC_NUMBER_TO_FAIL="+strconv.FormatInt(mallocNumToFail, 10))
 		if *mallocTestDebug {
 			shim.Env = append(shim.Env, "MALLOC_ABORT_ON_FAIL=1")
 		}