A solution to blocking, non-yielding function calls.

Bug: b/139010488
Change-Id: I8f2a9458980f83fbecafb22a5531aa6e3dbbc040
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/35573
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Tested-by: Ben Clayton <bclayton@google.com>