Disable integer_overflow sanitizer in libm.

Explicitly disables the integer_overflow sanitizer in the libm library.
This change should not impact any other build targets.

Bug: 30969751
Test: Built with and without SANITIZE_TARGET=integer_overflow
Change-Id: I98d0312344086b01394f456d4b953463b5e6cb1a
diff --git a/libm/Android.bp b/libm/Android.bp
index 07d4261..8947f4d 100644
--- a/libm/Android.bp
+++ b/libm/Android.bp
@@ -529,6 +529,7 @@
     sanitize: {
         address: false,
         coverage: false,
+        integer_overflow: false,
     },
     stl: "none",
 }