Executable multiple times larger using new LTS resolver

### General summary/comments

After changing the Stack resolver from 18.28 to 19.4, the built executable is much larger than before.

### Steps to reproduce

1. `stack new `
1. `cd `
1. Set resolver in stack.yaml to lts-18.28
1. Build the executable
1. Set resolver in stack.yaml to lts-19.4
1. Build the executable again

### Expected

The executables should be around the same size.

### Actual

The executable built using lts-18.28 is 826kB, while the one build using lts-19.4 is 5.1MB. I've seen a similar increase in size in 2 of my projects, one went from 21MB to 31MB and the other from 4MB to 15MB.

I have tried to reproduce this using just Cabal and also compilation straight through GHC. There was no change in size in these cases.