Uniquify test case descriptions

Make check-test-cases.py pass.

Prior to this commit, there were many repeated test descriptions, but
none with the same test data and dependencies and comments, as checked
with the following command:

    for x in tests/suites/*.data; do perl -00 -ne 'warn "$ARGV: $. = $seen{$_}\n" if $seen{$_}; $seen{$_}=$.' $x; done

Wherever a test suite contains multiple test cases with the exact same
description, add " [#1]", " [#2]", etc. to make the descriptions
unique. We don't currently use this particular arrangement of
punctuation, so all occurrences of " [#" were added by this script.

I used the following ad hoc code:

import sys

def fix_test_suite(data_file_name):
    in_paragraph = False
    total = {}
    index = {}
    lines = None
    with open(data_file_name) as data_file:
        lines = list(data_file.readlines())
        for line in lines:
            if line == '\n':
                in_paragraph = False
                continue
            if line.startswith('#'):
                continue
            if not in_paragraph:
                # This is a test case description line.
                total[line] = total.get(line, 0) + 1
                index[line] = 0
            in_paragraph = True
    with open(data_file_name, 'w') as data_file:
        for line in lines:
            if line in total and total[line] > 1:
                index[line] += 1
                line = '%s [#%d]\n' % (line[:-1], index[line])
            data_file.write(line)

for data_file_name in sys.argv[1:]:
    fix_test_suite(data_file_name)
diff --git a/tests/suites/test_suite_ecp.data b/tests/suites/test_suite_ecp.data
index 51f7e39..9219179 100644
--- a/tests/suites/test_suite_ecp.data
+++ b/tests/suites/test_suite_ecp.data
@@ -264,11 +264,11 @@
 depends_on:MBEDTLS_ECP_DP_SECP256R1_ENABLED
 mbedtls_ecp_check_pub_priv:MBEDTLS_ECP_DP_SECP256R1:"37cc56d976091e5a723ec7592dff206eee7cf9069174d0ad14b5f76822596292":"4ee500d82311ffea2fd2345d5d16bd8a88c26b770d55cd8a2a0efa01c8b4edfe":MBEDTLS_ECP_DP_SECP256R1:"00f12a1320760270a83cbffd53f6031ef76a5d86c8a204f2c30ca9ebf51f0f0ea7":"37cc56d976091e5a723ec7592dff206eee7cf9069174d0ad14b5f76822596292":"4ee500d82311ffea2fd2345d5d16bd8a88c26b770d55cd8a2a0efa01c8b4edfe":MBEDTLS_ERR_ECP_BAD_INPUT_DATA
 
-ECP gen keypair
+ECP gen keypair [#1]
 depends_on:MBEDTLS_ECP_DP_SECP192R1_ENABLED
 mbedtls_ecp_gen_keypair:MBEDTLS_ECP_DP_SECP192R1
 
-ECP gen keypair
+ECP gen keypair [#2]
 depends_on:MBEDTLS_ECP_DP_CURVE25519_ENABLED
 mbedtls_ecp_gen_keypair:MBEDTLS_ECP_DP_CURVE25519