Fixes a whole lot of leak-detector warnings.

Bug: b/133399620
Change-Id: I4f35150712dd2035a84c16d06ca75a4eba2c3c69
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31836Tested-by: Ben Clayton <bclayton@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>