Cleanup download scripts related to new Android NDK.

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1810603002

Review URL: https://codereview.chromium.org/1810603002

platform_tools/android/bin/android_gdb_native

@@ -45,8 +45,7 @@ GDBSETUP=$GDB_TMP_DIR/gdb.setup
 
 # Launch gdb client
 echo "Entering gdb client shell"
-GDB_COMMAND=$(command ls "$ANDROID_TOOLCHAIN"/*-gdb | head -n1)
-"$GDB_COMMAND" -x $GDBSETUP
+$ANDROID_TOOLCHAIN/../gdb -x $GDBSETUP
 
 # Clean up:
 # We could 'rm -rf $GDB_TMP_DIR', but doing so would cause subsequent debugging

platform_tools/android/bin/utils/setup_toolchain.sh

@@ -53,13 +53,14 @@ function default_toolchain() {
     pushd $TOOLCHAINS
     curl -o $NDK.zip https://dl.google.com/android/repository/android-ndk-$NDK-$HOST-x86_64.zip
     unzip $NDK.zip
-    UNZIPPED=android-ndk-$NDK-$HOST-x86_64.tar.bz2
+    UNZIPPED=android-ndk-$NDK
     ./$UNZIPPED/build/tools/make-standalone-toolchain.sh \
         --use-llvm              \
         --arch=$ANDROID_ARCH    \
         --platform=android-$API \
         --install_dir=$TOOLCHAIN
     cp $UNZIPPED/prebuilt/android-$ANDROID_ARCH/gdbserver/gdbserver $TOOLCHAIN
+    cp $UNZIPPED/prebuilt/${HOST}-x86_64/bin/gdb $TOOLCHAIN
     rm $NDK.zip
     rm -rf $UNZIPPED
     popd