Remove some regression tests we don't need

tests/regression.rs

@@ -75,18 +75,6 @@ fn test_it_converts(
     Arc::try_unwrap(png.raw).unwrap()
 }
 
-#[test]
-fn issue_29() {
-    test_it_converts(
-        "tests/files/issue-29.png",
-        None,
-        RGB,
-        BitDepth::Eight,
-        RGB,
-        BitDepth::Eight,
-    );
-}
-
 #[test]
 fn issue_42() {
     let input = "tests/files/issue-42.png";
@@ -102,78 +90,6 @@ fn issue_42() {
     );
 }
 
-#[test]
-fn issue_52_01() {
-    test_it_converts(
-        "tests/files/issue-52-01.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        INDEXED,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn issue_52_02() {
-    test_it_converts(
-        "tests/files/issue-52-02.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn issue_52_03() {
-    test_it_converts(
-        "tests/files/issue-52-03.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn issue_52_04() {
-    test_it_converts(
-        "tests/files/issue-52-04.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        RGB,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn issue_52_05() {
-    test_it_converts(
-        "tests/files/issue-52-05.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        RGB,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn issue_52_06() {
-    test_it_converts(
-        "tests/files/issue-52-06.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        RGBA,
-        BitDepth::Eight,
-    );
-}
-
 #[test]
 fn issue_56() {
     test_it_converts(
@@ -222,30 +138,6 @@ fn issue_60() {
     );
 }
 
-#[test]
-fn issue_80() {
-    test_it_converts(
-        "tests/files/issue-80.png",
-        None,
-        INDEXED,
-        BitDepth::Two,
-        INDEXED,
-        BitDepth::One,
-    );
-}
-
-#[test]
-fn issue_82() {
-    test_it_converts(
-        "tests/files/issue-82.png",
-        None,
-        INDEXED,
-        BitDepth::Four,
-        INDEXED,
-        BitDepth::Eight,
-    );
-}
-
 #[test]
 fn issue_89() {
     test_it_converts(
@@ -287,22 +179,6 @@ fn issue_92_filter_5() {
     );
 }
 
-#[test]
-fn issue_113() {
-    let input = "tests/files/issue-113.png";
-    let (output, mut opts) = get_opts(Path::new(input));
-    opts.interlace = Some(Interlacing::Adam7);
-    opts.optimize_alpha = true;
-    test_it_converts(
-        input,
-        Some((output, opts)),
-        RGBA,
-        BitDepth::Eight,
-        GRAYSCALE_ALPHA,
-        BitDepth::Eight,
-    );
-}
-
 #[test]
 fn issue_129() {
     test_it_converts(
@@ -327,30 +203,6 @@ fn issue_140() {
     );
 }
 
-#[test]
-fn issue_141() {
-    test_it_converts(
-        "tests/files/issue-141.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        RGB,
-        BitDepth::Eight,
-    );
-}
-
-#[test]
-fn issue_153() {
-    test_it_converts(
-        "tests/files/issue-153.png",
-        None,
-        RGBA,
-        BitDepth::Eight,
-        INDEXED,
-        BitDepth::Eight,
-    );
-}
-
 #[test]
 fn issue_159() {
     test_it_converts(