Check expect Python version loaded in test scripts (#26369)

Add a check to Python version-pinned test scripts that the expected
version of Python was loaded.

This is analogous to what we already do for LLVM version-pinned tests.

While here, also remove the unused Python 2.7 test script.

Resolves https://github.com/Cray/chapel-private/issues/3717.

[reviewed by @lydia-duncan , thanks!]

Testing:
- [x] manual run of each Python test script gets past check
- [x] error emitted as expected for wrong Python version

util/cron/common-python.bash

@@ -2,36 +2,15 @@
 
 # a helper function to select python versions before running `nightly` but
 # *after* sourcing other `common*.bash`
-function set_python_version() {
+function set_and_check_python_version() {
   local ver_str=$1
 
-  # make sure the length is OK
-  if [[ ${#ver_str} -lt 3 ]] || [[ ${#ver_str} -gt 4 ]]; then
-    echo "Python version string must be in format 'x.y[z]'"
-    return 1
-  fi
-
-  # make sure the 2nd char is "."
-  if [[ "${ver_str:1:1}" != "." ]]; then
-    echo "Python version string must be in format 'x.y[z]'"
-    return 1
-  fi
-
-  local major_ver=${ver_str:0:1}
-  local minor_ver=${ver_str:2}
+  local major_ver=$(echo $ver_str | cut -d. -f1)
+  local minor_ver=$(echo $ver_str | cut -d. -f2)
 
   # override `python`
   export PATH=/hpcdc/project/chapel/no-python:$PATH
 
-  if [[ $major_ver -eq 2 ]]; then
-    # Do some special casing for python2:
-    # 1. Avoid using chpl_make.py and other python scripts as much as possible
-    # 2. Override `python3`
-
-    export CHPL_NIGHTLY_MAKE=gmake
-    export PATH=/hpcdc/project/chapel/no-python3:$PATH
-  fi
-
   local setup_script="/hpcdc/project/chapel/setup_python$major_ver$minor_ver.bash"
 
   if [[ -f "${setup_script}" ]] ; then
@@ -41,11 +20,20 @@ function set_python_version() {
     return 1
   fi
 
-  if [[ $major_ver -eq 2 ]]; then
-    echo "Using $(python2 --version 2>&1)"
-  else
-    echo "Using $(python3 --version)"
-  fi
+  check_python_version $ver_str
+
+  echo "Using $(python3 --version)"
 }
 
+# Check correct Python version loaded, exiting with error if not
+function check_python_version() {
+  local expected_python_version=$1
 
+  local actual_python_version=$(python3 --version | cut -d' ' -f2)
+
+  if [ "$actual_python_version" != "$expected_python_version" ]; then
+    echo "Wrong Python version"
+    echo "Expected Version: $expected_python_version. Actual Version: $actual_python_version"
+    exit 2
+  fi
+}

util/cron/test-linux64-python35.bash

@@ -8,6 +8,6 @@ source $UTIL_CRON_DIR/common-python.bash
 
 export CHPL_NIGHTLY_TEST_CONFIG_NAME="linux64-python35"
 
-set_python_version "3.5"
+set_and_check_python_version "3.5.2"
 
 $UTIL_CRON_DIR/nightly -cron -pythonDep ${nightly_args}

util/cron/test-linux64-python36.bash

@@ -8,6 +8,6 @@ source $UTIL_CRON_DIR/common-python.bash
 
 export CHPL_NIGHTLY_TEST_CONFIG_NAME="linux64-python36"
 
-set_python_version "3.6"
+set_and_check_python_version "3.6.10"
 
 $UTIL_CRON_DIR/nightly -cron -pythonDep ${nightly_args}

util/cron/test-linux64-python37.bash

@@ -8,6 +8,6 @@ source $UTIL_CRON_DIR/common-python.bash
 
 export CHPL_NIGHTLY_TEST_CONFIG_NAME="linux64-python37"
 
-set_python_version "3.7"
+set_and_check_python_version "3.7.9"
 
 $UTIL_CRON_DIR/nightly -cron -pythonDep ${nightly_args}

util/cron/test-linux64-python39.bash

@@ -8,6 +8,6 @@ source $UTIL_CRON_DIR/common-python.bash
 
 export CHPL_NIGHTLY_TEST_CONFIG_NAME="linux64-python39"
 
-set_python_version "3.9"
+set_and_check_python_version "3.9.13"
 
 $UTIL_CRON_DIR/nightly -cron -hellos ${nightly_args}