Disable unsafe FP math optimizations for LLVM 7.0.
Disable unsafe FP math optimizations for LLVM 7.0.

Failures in dEQP using SwiftShader with LLVM 7.0 were caused by unsafe
floating point math optimizations, which are more aggressive than with
LLVM 3.0.

Bug b/115344057

Change-Id: Idf564d0193efba37cd1192a188b18a5f8b4ed4f7
Reviewed-on: https://swiftshader-review.googlesource.com/20708
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@google.com>
Reviewed-by: Shannon Woods <0f3694938fd5703bd548127ee497e4d604509bef@google.com>

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