ReactorUnitTests: Speed up multithreaded tests

Reduce number of threads and iterations.
These tests were taking a long time.

Should around ~16x faster.

Bug: b/153803432
Change-Id: I3b0e6753852e7bb3a4ed44359e7d8446fd4120eb
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/44408
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
diff --git a/src/Reactor/ReactorUnitTests.cpp b/src/Reactor/ReactorUnitTests.cpp
index adb0cb4..250a8c7 100644
--- a/src/Reactor/ReactorUnitTests.cpp
+++ b/src/Reactor/ReactorUnitTests.cpp
@@ -2951,8 +2951,8 @@
 
 TEST(ReactorUnitTests, Multithreaded_Function)
 {
-	constexpr int numThreads = 32;
-	constexpr int numLoops = 64;
+	constexpr int numThreads = 8;
+	constexpr int numLoops = 16;
 
 	auto threads = std::unique_ptr<std::thread[]>(new std::thread[numThreads]);
 	auto results = std::unique_ptr<int[]>(new int[numThreads * numLoops]);
@@ -3000,8 +3000,8 @@
 		return;
 	}
 
-	constexpr int numThreads = 32;
-	constexpr int numLoops = 64;
+	constexpr int numThreads = 8;
+	constexpr int numLoops = 16;
 
 	struct Result
 	{