perf test java symbol: Remove needless debuginfod queries

Test case 'Test java symbol' might run for a long time. On Fedora 38 the
run time is very, very long:

  Output before:
  # time ./perf test 108
  108: Test java symbol                  : Ok
  real   22m15.775s
  user   3m42.584s
  sys    4m30.685s
  #

The reason is a lookup for the server for debug symbols as shown in:

  # cat /etc/debuginfod/elfutils.urls
  https://debuginfod.fedoraproject.org/
  #

This lookup is done for every symbol/sample, so about 3500 lookups
will take place.

To omit this lookup, which is not needed, unset environment variable
DEBUGINFOD_URLS=''.

  Output after:
  # time ./perf test 108
  108: Test java symbol                  : Ok

  real	0m6.242s
  user	0m4.982s
  sys	0m3.243s
  #

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/20230509131847.835974-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: Thomas Richter

tools/perf/tests/shell/test_java_symbol.sh

@@ -56,7 +56,7 @@ if [ $? -ne 0 ]; then
 	exit 1
 fi
 
-if ! perf inject -i $PERF_DATA -o $PERF_INJ_DATA -j; then
+if ! DEBUGINFOD_URLS='' perf inject -i $PERF_DATA -o $PERF_INJ_DATA -j; then
 	echo "Fail to inject samples"
 	exit 1
 fi