Remove uses of libabsl_headers.

These modules already have dependencies on libabsl, which exposes
the same set of headers.

Bug: 246681282
Test: presubmit
Change-Id: I5f9302943360261ee5bcb6d7f87f884287c36345
diff --git a/Android.bp b/Android.bp
index ba5c920..67d9d24 100644
--- a/Android.bp
+++ b/Android.bp
@@ -166,9 +166,6 @@
         "libclang-cpp_host",
         "libziparchive",
     ],
-    header_libs: [
-        "libabsl_headers",
-    ],
     static_libs: [
         "kythe_cxx_glog",
         "kythe_cxx_common",
@@ -197,9 +194,6 @@
         "kythe/cxx/extractor/proto/proto_extractor_main.cc",
         "kythe/cxx/indexer/proto/search_path.cc",
     ],
-    header_libs: [
-        "libabsl_headers",
-    ],
     static_libs: [
         "kythe_cxx_glog",
         "kythe_cxx_common",
@@ -232,9 +226,6 @@
     srcs: [
         "kythe/cxx/tools/proto_metadata_plugin.cc",
     ],
-    header_libs: [
-        "libabsl_headers",
-    ],
     static_libs: [
         "kythe_cxx_glog",
         "kythe_cxx_common",