Remove `gdbserver` from `PRODUCT_PACKAGES_DEBUG` in `base_system.mk`.

The `gdbserver` binaries have been removed from Android sources
(https://android-review.googlesource.com/c/platform/prebuilts/misc/+/1748908/).

Test: m
Change-Id: I8e3001508360906f3fe86830b81fb94b01a5ac74
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 68dd980..760f8fb 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -362,7 +362,6 @@
     adb_keys \
     arping \
     dmuserd \
-    gdbserver \
     idlcli \
     init-debug.rc \
     iotop \