Fix build: Do not return stack temporary.
Fix build: Do not return stack temporary.

Bug: b/139528538
Change-Id: I11d25399f582393ede13cbd8349c79cb3fdf4053
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/38608
Reviewed-by: Ben Clayton <1f693eb7158dc33015048c09d6712f74dabddf79@google.com>
Tested-by: Ben Clayton <1f693eb7158dc33015048c09d6712f74dabddf79@google.com>

bkaradzic/SwiftShader,bkaradzic/SwiftShader,bkaradzic/SwiftShader,google/swiftshader,bkaradzic/SwiftShader,google/swiftshader,google/swiftshader,bkaradzic/SwiftShader