Don't involve debuggerd in a SIGFPE test.

We just want to check that SIGFPE is raised, not try to "debug" this
expected behavior.

Bug: http://b/180605583
Test: check logs
Change-Id: I11571e02c4608570e0d406adeabc36186c5bb107
diff --git a/tests/fenv_test.cpp b/tests/fenv_test.cpp
index 89c7fd5..d495970 100644
--- a/tests/fenv_test.cpp
+++ b/tests/fenv_test.cpp
@@ -202,6 +202,7 @@
   ASSERT_NE(-1, pid) << strerror(errno);
 
   if (pid == 0) {
+    signal(SIGFPE, SIG_DFL);  // Disable debuggerd.
     feclearexcept(FE_ALL_EXCEPT);
     ASSERT_EQ(0, fetestexcept(FE_ALL_EXCEPT));
     ASSERT_EQ(0, feenableexcept(FE_INVALID));