threads test: increase threads heap size

Author: maciejbocianski

TESTS/mbedmicro-rtos-mbed/threads/main.cpp

@@ -26,8 +26,8 @@
 #endif
 
 #define THREAD_STACK_SIZE 512
-#define PARALLEL_THREAD_STACK_SIZE 256
-#define CHILD_THREAD_STACK_SIZE 192
+#define PARALLEL_THREAD_STACK_SIZE 384
+#define CHILD_THREAD_STACK_SIZE 384
 
 using namespace utest::v1;