Reduce size of release binary (#592)

This PR makes 3 changes that together reduce binary size by around 25%:
- Sets lto="fat" in cargo.toml
- Sets panic="abort" in cargo.toml
- Sets location-detail=none in RUSTFLAGS

Closes #571

An unrelated change: I've replaced the zopfli test file with a smaller
one that runs much faster, as well as removing the slow test for
issue-133 which was related to an older alpha optimisation that is no
longer relevant.

.github/workflows/oxipng.yml

@@ -55,6 +55,7 @@ jobs:
 
  env:
  CARGO_BUILD_TARGET: ${{ matrix.target }}
+ RUSTFLAGS: -Zlocation-detail=none
 
  steps:
  - name: Checkout source

Cargo.toml

@@ -95,8 +95,6 @@ path = "src/lib.rs"
 opt-level = 2
 
 [profile.release]
-lto = "thin"
+lto = "fat"
 strip = "symbols"
-
-[profile.dev.package.bitvec]
-opt-level = 3
+panic = "abort"

tests/flags.rs

@@ -686,9 +686,9 @@ fn zopfli_mode() {
  input,
  &output,
  &opts,
- RGB,
+ INDEXED,
  BitDepth::Eight,
- RGB,
+ INDEXED,
  BitDepth::Eight,
  );
 }

tests/regression.rs

@@ -315,21 +315,6 @@ fn issue_129() {
  );
 }
 
-#[test]
-fn issue_133() {
- let input = "tests/files/issue-133.png";
- let (output, mut opts) = get_opts(Path::new(input));
- opts.optimize_alpha = true;
- test_it_converts(
- input,
- Some((output, opts)),
- RGBA,
- BitDepth::Eight,
- RGBA,
- BitDepth::Eight,
- );
-}
-
 #[test]
 fn issue_140() {
  test_it_converts(