Constructor overloads in Reactor is causing the build on Android to fail.

Change-Id: I446b345d420b8789ece77a245b2cd3eab8499e35
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/28444Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Presubmit-Ready: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Chris Forbes <chrisforbes@google.com>