Ignore unrecognized VM options in desugar.sh, such as the JVM 9 flags to silence warnings.

This prevents stopping the build when invoking desugar with JDK 8.

RELNOTES: None.
PiperOrigin-RevId: 210172285
diff --git a/tools/android/desugar.sh b/tools/android/desugar.sh
index 1c98306..2f34e77 100644
--- a/tools/android/desugar.sh
+++ b/tools/android/desugar.sh
@@ -122,6 +122,7 @@
       done
 
       "${DESUGAR}" \
+          "--jvm_flag=-XX:+IgnoreUnrecognizedVMOptions" \
           "--jvm_flags=--add-opens=java.base/java.lang.invoke=ALL-UNNAMED" \
           "--jvm_flags=--add-opens=java.base/java.nio=ALL-UNNAMED" \
           "--jvm_flags=--add-opens=java.base/java.lang=ALL-UNNAMED" \
@@ -134,6 +135,7 @@
 fi
 
 "${DESUGAR}" \
+    "--jvm_flag=-XX:+IgnoreUnrecognizedVMOptions" \
     "--jvm_flags=--add-opens=java.base/java.lang.invoke=ALL-UNNAMED" \
     "--jvm_flags=--add-opens=java.base/java.nio=ALL-UNNAMED" \
     "--jvm_flags=--add-opens=java.base/java.lang=ALL-UNNAMED" \