ART: Increase stack overflow guard for x86 sanitization

There's another increase necessary for 32-bit x86.

Bug: 31098551
Test: m SANITIZE_HOST=address test-art-host
Change-Id: I35e665e499f90fb3ba0afc5f61cc1a3edac91a39
diff --git a/build/art.go b/build/art.go
index 9de2b05..f52c635 100644
--- a/build/art.go
+++ b/build/art.go
@@ -87,7 +87,7 @@
 				"-DART_STACK_OVERFLOW_GAP_arm64=8192",
 				"-DART_STACK_OVERFLOW_GAP_mips=16384",
 				"-DART_STACK_OVERFLOW_GAP_mips64=16384",
-				"-DART_STACK_OVERFLOW_GAP_x86=12288",
+				"-DART_STACK_OVERFLOW_GAP_x86=16384",
 				"-DART_STACK_OVERFLOW_GAP_x86_64=20480")
 	} else {
 		cflags = append(cflags,