test: skip sv2 TPTester tests on Windows

The template_provider_tests `client_tests`, `fee_timer_blocking_test`
and `new_tip_bypasses_fee_timer_test` cases each construct and tear
down a TPTester. Like the lifecycle test skipped in the previous
commit, that teardown deadlocks intermittently on Windows in
std::thread::join during libmultiprocess thread-local state cleanup.
This is a known libmultiprocess Windows issue, not specific to
sv2-tp:

  bitcoin-core/libmultiprocess#231
  bitcoin/bitcoin#32387

Gate the three TPTester-using cases off on _WIN32 with a TODO. The
non-IPC test `block_reserved_weight_floor` continues to run on
Windows.

Assisted-by: GitHub Copilot
Assisted-by: Anthropic Claude Opus 4

Author: Sjors

src/test/sv2_template_provider_tests.cpp

@@ -38,6 +38,12 @@ BOOST_AUTO_TEST_CASE(block_reserved_weight_floor)
     BOOST_REQUIRE_EQUAL(options.block_reserved_weight, node::MIN_BLOCK_RESERVED_WEIGHT);
 }
 
+// TODO: Re-enable on Windows once the libmultiprocess shutdown hang is fixed
+// upstream. Tearing down TPTester (and with it the IPC EventLoop / per-thread
+// state) deadlocks in std::thread::join on mingw winpthreads. This is a known
+// libmultiprocess Windows issue, not specific to sv2-tp. Tracked in
+// libmultiprocess#231 and bitcoin#32387.
+#ifndef WIN32
 BOOST_AUTO_TEST_CASE(client_tests)
 {
     TPTester tester{};
@@ -282,5 +288,6 @@ BOOST_AUTO_TEST_CASE(new_tip_bypasses_fee_timer_test)
 
     tester.m_mining_control->Shutdown();
 }
+#endif // !WIN32
 
 BOOST_AUTO_TEST_SUITE_END()