CI: Move Android NDK to stable path

Author: dg0yt

ci/azure-pipelines.yml

@@ -117,6 +117,7 @@ jobs:
           -D$(TARGET)_INSTALL_PREFIX=/usr
           -D$(TARGET)_TOOLCHAIN_DIR=$(SUPERBUILD_INSTALL_DIR)/$(TARGET)/toolchain
           -DMapper_CI_GDAL_DATA_DIR=$(SUPERBUILD_INSTALL_DIR)/$(TARGET)/usr/share/gdal
+          -DANDROID_NDK_INSTALL_ROOT=/Users/vsts
           -DANDROID_BUILD_LIBCXX=1
         buildArgs: -j5
         toolchainTargets: