Remove a stray newline.

err() not only adds its own newline, it'll add the strerror() output
first, so this stray newline messes up the error message. (Seen running
bionic benchmarks not as root, which causes the std_map benchmarks to
fail, which is especially annoying because it ends the whole benchmark
run, not just the specific benchmark, but that's a less obvious fix, so
I'm just fixing the trivial part here!)

Test: treehugger
Change-Id: I7e87ea4385c410942fbdd14e6fdfddbf7320082a
diff --git a/benchmarks/malloc_map_benchmark.cpp b/benchmarks/malloc_map_benchmark.cpp
index 5757325..04c9a07 100644
--- a/benchmarks/malloc_map_benchmark.cpp
+++ b/benchmarks/malloc_map_benchmark.cpp
@@ -52,7 +52,7 @@
         android::base::StartsWith(vma.name, "[anon:GWP-ASan")) {
       android::meminfo::Vma update_vma(vma);
       if (!proc_mem.FillInVmaStats(update_vma)) {
-        err(1, "FillInVmaStats failed\n");
+        err(1, "FillInVmaStats failed");
       }
       *rss_bytes += update_vma.usage.rss;
     }