art: remove unnecessary references to external/zlib.

Bug: https://issuetracker.google.com/115695768
Test: builds
Change-Id: If28672497d5702e084ac033eceaeb31a18eb292e
diff --git a/compiler/Android.bp b/compiler/Android.bp
index 52bd89f..3198069 100644
--- a/compiler/Android.bp
+++ b/compiler/Android.bp
@@ -450,10 +450,6 @@
         "libnativeloader",
     ],
 
-    include_dirs: [
-        "external/zlib",
-    ],
-
     target: {
         host: {
             shared_libs: [
diff --git a/dex2oat/Android.bp b/dex2oat/Android.bp
index 149d758..d4b2ae6 100644
--- a/dex2oat/Android.bp
+++ b/dex2oat/Android.bp
@@ -459,9 +459,6 @@
     },
 
     header_libs: ["dex2oat_headers"],
-    include_dirs: [
-        "external/zlib",
-    ],
     shared_libs: [
         "libartbased",
         "libartd-compiler",
diff --git a/libdexfile/Android.bp b/libdexfile/Android.bp
index 30d1bcd..8e131d3 100644
--- a/libdexfile/Android.bp
+++ b/libdexfile/Android.bp
@@ -200,9 +200,6 @@
         "libbacktrace",
         "libziparchive",
     ],
-    include_dirs: [
-        "external/zlib",
-    ],
 }
 
 cc_library_headers {
diff --git a/runtime/Android.bp b/runtime/Android.bp
index 950ecd9..2d15e4a 100644
--- a/runtime/Android.bp
+++ b/runtime/Android.bp
@@ -384,7 +384,6 @@
     export_generated_headers: ["cpp-define-generator-asm-support"],
     include_dirs: [
         "art/sigchainlib",
-        "external/zlib",
     ],
     header_libs: [
         "art_cmdlineparser_headers",
@@ -663,9 +662,6 @@
     header_libs: [
         "art_cmdlineparser_headers", // For parsed_options_test.
     ],
-    include_dirs: [
-        "external/zlib",
-    ],
 }
 
 art_cc_test {