Avoid allocation when storing jemalloc profile name

[antonio2368]

Changelog category (leave one):

• Not for changelog (changelog entry is not required)

We cannot allocate in MemoryTracker in all cases.

https://github.com/ClickHouse/clickhouse-private/issues/38064

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

[clickhouse-gh]

Workflow [PR], commit [0ba634a]

Summary: ❌

job_name	test_name	status	info	comment
AST fuzzer (amd_debug)		failure
	Task failed: $?=1	FAIL
AST fuzzer (arm_asan)		failure
	Task failed: $?=1	FAIL
AST fuzzer (amd_tsan)		failure
	Task failed: $?=1	FAIL
AST fuzzer (amd_msan)		failure
	Task failed: $?=1	FAIL
AST fuzzer (amd_ubsan)		failure
	Task failed: $?=1	FAIL
BuzzHouse (amd_debug)		failure
	Task failed: $?=1	FAIL
BuzzHouse (arm_asan)		failure
	Task failed: $?=1	FAIL
BuzzHouse (amd_tsan)		failure
	Task failed: $?=1	FAIL
BuzzHouse (amd_msan)		failure
	Task failed: $?=1	FAIL
BuzzHouse (amd_ubsan)		failure
	Task failed: $?=1	FAIL

[azat]

LGTM

Also, it looks like we can update the callers of flushProfile, i.e.

$ git di
diff --git a/src/Coordination/FourLetterCommand.cpp b/src/Coordination/FourLetterCommand.cpp
index e7ed119c0cc..02e5d4d1daf 100644
--- a/src/Coordination/FourLetterCommand.cpp
+++ b/src/Coordination/FourLetterCommand.cpp
@@ -652,8 +652,8 @@ String JemallocDumpStats::run()

 String JemallocFlushProfile::run()
 {
-    Jemalloc::flushProfile("/tmp/jemalloc_keeper");
-    return std::string{Jemalloc::getLastFlushProfileForThread()};
+    auto profile_path = Jemalloc::flushProfile("/tmp/jemalloc_keeper");
+    return profile_path;
 }

 String JemallocEnableProfile::run()
diff --git a/src/Interpreters/InterpreterSystemQuery.cpp b/src/Interpreters/InterpreterSystemQuery.cpp
index df806db9eee..a137483b8a0 100644
--- a/src/Interpreters/InterpreterSystemQuery.cpp
+++ b/src/Interpreters/InterpreterSystemQuery.cpp
@@ -915,10 +915,9 @@ BlockIO InterpreterSystemQuery::execute()
         case Type::JEMALLOC_FLUSH_PROFILE:
         {
             getContext()->checkAccess(AccessType::SYSTEM_JEMALLOC);
-            Jemalloc::flushProfile(query.jemalloc_profile_path.empty() ? "/tmp/jemalloc_clickhouse" : query.jemalloc_profile_path);
-            auto filename = Jemalloc::getLastFlushProfileForThread();
+            auto profile_path = Jemalloc::flushProfile(query.jemalloc_profile_path.empty() ? "/tmp/jemalloc_clickhouse" : query.jemalloc_profile_path);
             auto col = ColumnString::create();
-            col->insertData(filename.data(), filename.size());
+            col->insertData(profile_path.data(), profile_path.size());
             Columns columns;
             columns.emplace_back(std::move(col));
             Chunk chunk(std::move(columns), 1);

[azat]

I need this changes to avoid conflicts, merging.

CI is unrelated (fixed in #87339)