Cherry-pick a few tcu::StringTemplate fixes to master
Cherry-pick a few tcu::StringTemplate fixes to master

Change-Id: I5a2d88b78b2fe40e62a510c68c58ecc39d033a9f

KhronosGroup/Vulkan-CTS,chadversary/deqp,chadversary/deqp,KhronosGroup/Vulkan-CTS,KhronosGroup/Vulkan-CTS,chadversary/deqp,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/Vulkan-CTS,chadversary/deqp,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,KhronosGroup/VK-GL-CTS,googlestadia/VK-GL-CTS,googlestadia/VK-GL-CTS,chadversary/deqp,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,KhronosGroup/Vulkan-CTS,KhronosGroup/VK-GL-CTS,chadversary/deqp