shtests: Stop requiring a tty

It is desirable to be able to run the tests on a system without
a functioning tty. Since this distribution comes with its own
pseudo-tty facility, pty, it should be possible to run the few
tests that require a tty on the pseudo-tty instead. I've verified
that they fail as expected on older ksh93.

Discussion: https://github.com/ksh93/ksh/pull/171

src/cmd/ksh93/tests/basic.sh,
src/cmd/ksh93/tests/bracket.sh:
- Remove tests that require a tty.

src/cmd/ksh93/tests/pty.sh:
- Put them here, adapted to work as interactive pty scripts.

src/cmd/ksh93/tests/shtests:
- No longer refuse to run if there is no functioning tty.

.github/workflows/ci.yml:
- Since the tests no longer require a tty, no longer use script(1)
  to get a pseudo-tty. Let's see if this works...
- Re-enable the Mac runner (re: 14632361). Maybe it has improved.

.github/workflows/ci.yml

@@ -14,19 +14,46 @@ jobs:
       run: bin/package make
     - name: Regression tests
       run: |
-        PS4="$PS4 [ci.yml] "
+        PS4="$PS4[ci.yml] "
         set -o xtrace
         export TZ=UTC
         ulimit -n 1024
         : default regression tests &&
-        script -q -e -c "bin/shtests" &&
+        bin/shtests &&
         : regression tests with OS-provided UTF-8 locales &&
-        LANG=nl_NL.UTF-8 script -q -e -c "bin/shtests --locale --nocompile" &&
-        LANG=ja_JP.UTF-8 script -q -e -c "bin/shtests --locale --nocompile" &&
+        LANG=nl_NL.UTF-8 bin/shtests --locale --nocompile &&
+        LANG=ja_JP.UTF-8 bin/shtests --locale --nocompile &&
         : disable most SHOPTs, rebuild ksh &&
         sed --regexp-extended --in-place=.orig \
           '/^SHOPT (2DMATCH|AUDIT|BGX|BRACEPAT|DYNAMIC|EDPREDICT|ESH|FIXEDARRAY|HISTEXPAND|MULTIBYTE|NAMESPACE|OPTIMIZE|SUID_EXEC|STATS|VSH)=/ s/=1/=0/' \
           src/cmd/ksh93/SHOPT.sh &&
         bin/package make &&
         : default regression tests with SHOPTs disabled &&
-        script -q -e -c "bin/shtests"
+        bin/shtests
+
+  MacOS:
+    name: macOS
+    runs-on: macos-latest
+    steps:
+    - name: Checkout sources
+      uses: actions/checkout@v2
+    - name: Build
+      run: bin/package make
+    - name: Regression tests
+      run: |
+        PS4="$PS4[ci.yml] "
+        set -o xtrace
+        export TZ=UTC
+        ulimit -n 1024
+        : default regression tests &&
+        bin/shtests &&
+        : regression tests with OS-provided UTF-8 locales &&
+        LANG=nl_NL.UTF-8 bin/shtests --locale --nocompile &&
+        LANG=ja_JP.UTF-8 bin/shtests --locale --nocompile &&
+        : disable most SHOPTs, rebuild ksh &&
+        sed -E -i.orig \
+          '/^SHOPT (2DMATCH|AUDIT|BGX|BRACEPAT|DYNAMIC|EDPREDICT|ESH|FIXEDARRAY|HISTEXPAND|MULTIBYTE|NAMESPACE|OPTIMIZE|SUID_EXEC|STATS|VSH)=/ s/=1/=0/' \
+          src/cmd/ksh93/SHOPT.sh &&
+        bin/package make &&
+        : default regression tests with SHOPTs disabled &&
+        bin/shtests