Move frameworks/native/include from -isystem to -I

-isystem hides all warnings.  The warnings in frameworks/native/include
have been cleaned up, so move it from -isystem to -I.

Test: m -j checkbuild
Bug: 31752268
Change-Id: Ie3656348b5b2a1828dec790aa047635ac0fe6d86
diff --git a/cc/config/global.go b/cc/config/global.go
index 0a7bdc5..ae43301 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -95,6 +95,7 @@
 	pctx.PrefixedPathsForOptionalSourceVariable("CommonGlobalIncludes", "-I",
 		[]string{
 			"system/core/include",
+			"frameworks/native/include",
 		})
 	pctx.PrefixedPathsForOptionalSourceVariable("CommonGlobalSystemIncludes", "-isystem ",
 		[]string{
@@ -103,7 +104,6 @@
 			"hardware/libhardware_legacy/include",
 			"hardware/ril/include",
 			"libnativehelper/include",
-			"frameworks/native/include",
 			"frameworks/native/opengl/include",
 			"frameworks/av/include",
 			"frameworks/base/include",