init: only use signed-integer-overflow sanitizer

We've blown up twice in init due to the unsigned integer overflow
sanitizer despite the overflows in question being both defined and
intentional.

Bug: 63680332
Test: boot
Change-Id: I08effe3202ac1367d858982ff5478b3a088bab37
(cherry picked from commit 2ffd65e1d1)

init/Android.bp

@@ -18,7 +18,7 @@ cc_defaults {
     name: "init_defaults",
     cpp_std: "experimental",
     sanitize: {
-        misc_undefined: ["integer"],
+        misc_undefined: ["signed-integer-overflow"],
     },
     cppflags: [
         "-DLOG_UEVENTS=0",

init/Android.mk

@@ -96,6 +96,6 @@ LOCAL_POST_INSTALL_CMD := $(hide) mkdir -p $(TARGET_ROOT_OUT)/sbin; \
     ln -sf ../init $(TARGET_ROOT_OUT)/sbin/ueventd; \
     ln -sf ../init $(TARGET_ROOT_OUT)/sbin/watchdogd
 
-LOCAL_SANITIZE := integer
+LOCAL_SANITIZE := signed-integer-overflow
 LOCAL_CLANG := true
 include $(BUILD_EXECUTABLE)