spdlog: add run_tests.sh (google#13598)

`infra/experimental/chronos/check_tests.sh spdlog c`

```
Test project /src/spdlog                                                                                                                13:06:09 [23/1817]
    Start 1: spdlog-utests                                                   
1/1 Test #1: spdlog-utests ....................   Passed    5.55 sec                                                                                      
                                                                                                                                                          
100% tests passed, 0 tests failed out of 1                                                                                                                
                                                                             
Total Test time (real) =   5.55 sec
```

Signed-off-by: Adam Korczynski <adam@adalogics.com>

Author: AdamKorcz

projects/spdlog/Dockerfile

@@ -20,5 +20,5 @@ RUN apt-get update && apt-get install --yes cmake
 RUN git clone --depth 1 https://github.com/gabime/spdlog.git
 RUN zip spdlog_fuzzer_seed_corpus.zip spdlog/example/*
 WORKDIR spdlog
-COPY build.sh spdlog_fuzzer.dict $SRC/
+COPY build.sh run_tests.sh spdlog_fuzzer.dict $SRC/
 COPY fuzz/* $SRC/

projects/spdlog/build.sh

@@ -16,7 +16,7 @@
 ################################################################################
 
 # build project
-cmake . && make -j$(nproc)
+cmake -DSPDLOG_BUILD_TESTS=ON . && make -j$(nproc)
 
 # build fuzzers
 for f in $(find $SRC -name '*_fuzzer.cc'); do

projects/spdlog/run_tests.sh

@@ -0,0 +1,18 @@
+#!/bin/bash -eu
+# Copyright 2025 Google LLC.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+################################################################################
+
+ctest -j 4 --output-on-failure