Update prebuilts to go 1.13

From https://ci.android.com/builds/submitted/5859978/linux/latest/go.zip

Test: m blueprint_tools
Change-Id: Ief07b24cffce02195326d627f28ba879e8f14f6b
diff --git a/src/runtime/mstats.go b/src/runtime/mstats.go
index 9250865..421580e 100644
--- a/src/runtime/mstats.go
+++ b/src/runtime/mstats.go
@@ -470,6 +470,9 @@
 	})
 }
 
+// readGCStats_m must be called on the system stack because it acquires the heap
+// lock. See mheap for details.
+//go:systemstack
 func readGCStats_m(pauses *[]uint64) {
 	p := *pauses
 	// Calling code in runtime/debug should make the slice large enough.